Colonic Investigation following acute diverticulitis in Northland, New Zealand
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Diverticular disease is extremely common in the Western world and is increasing in incidence, especially in younger patients.[[1]] Diverticulitis is a common manifestation of diverticular disease, and one of the commonest reasons for general surgical hospital admission.[[2]] It is associated with an increased mortality risk in patients at five years follow-up.[[3]] Treatment in hospital usually consists of intravenous antibiotic and supportive measures.[[4]] Occasional operative intervention is needed, but the majority of patients are discharged without undergoing colonic resection.[[5]]
Follow up, investigation and long-term management of these patients remains controversial, and is heavily dependent on resource availability.
Diverticulitis can be categorised as complicated or uncomplicated, which is determined radiologically with HR-CT (high resolution computed tomography) imaging.[[6]] In those with complicated diverticulitis, the rate of malignancy is estimated to be as high as 10%, compared to 0.7% in those with uncomplicated disease.[[7]] Historically, international guidelines including the American Gastroenterology Association (AGA)[[8]] guidelines, have suggested colonic investigation in all patients following resolution of acute diverticulitis; however, these recommendations are based on older data and expert opinion,[[9]] are likely to be outdated and do not take into account resource availability.
More recent guidelines from Society of American Gastrointestinal and Endoscopic Surgeons (SAGES)[[10]] and European Society of Coloproctology (ESC) recommend colonic investigation (colonoscopy or CT colonography) in patients with complicated diverticulitis only.[[11]] This is due to developments in CT imaging quality, and more recent meta-analyses that have shown the prevalence of colorectal cancer (CRC) in uncomplicated patients is low.[[12,13]] Interestingly although the overall rate of diverticulitis is increasing the prevalence of complicated disease has remained static.[[3]]
New Zealand has high rates of colonic cancer,[[14]] and worse outcomes compared to other countries.[[15]] There is also increasing pressure on endoscopy units throughout New Zealand, especially with bowel cancer screening being rolled out nationally. Decision making around selecting the most appropriate patients for whom to perform colonic investigation is therefore important in a resource constrained environment.
The aim of this study was to investigate which patients in Northland undergo colonic investigation following an episode of diverticulitis, define malignancy detection rate and aid in the formulation of local guidelines.
Methods
Setting
Whangārei Hospital is the largest hospital (249 beds) in Northland, New Zealand. It has the only General Surgical Unit in Northland, as well as the only hospital with CT and intensive care capability, and serves a population of 194,600.[[16]] During the study period there was no hospital policy regarding colonic investigation following an episode of diverticulitis. This decision was at the discretion of the treating clinician.
Study design
A retrospective study of all adults aged >18 who were admitted to Whangārei Hospital with diverticulitis between 1 January 2015 and 31 December 2019 was performed. Patients were identified using the International Classification of Disease, 10th revision code (see Appendix 1). Electronic medical records including emergency department (ED) notes, operation notes, and written clinical notes were interrogated to confirm inclusion criteria and record clinical outcomes. Baseline demographics, diverticulitis grading and complications, operative management and complications, length of stay, and 30-day, 90-day and 1-year readmission rates were collected.
Inclusion and exclusion criteria
Patients were excluded if aged younger than 18 years. The first presentation with diverticulitis during the study period was included with readmission data collected but not included as a separate case. Patients were excluded if a colonoscopy or CT colonography had been performed within three years.
Diverticulitis complexity
Patients were grouped into two groups based on the complexity of their diverticulitis. The Hinchey classification was used.[[6]] Uncomplicated diverticulitis was defined as Hinchey grade 1a and an absence of perforation, abscess or fistula. Hinchey Classification Grade was determined based on a CT report from a consultant radiologist or operative findings.
Outcomes of interest
The primary outcome of interest is rate of colonic investigation following admission for diverticulitis, according to diverticulitis severity grade. Secondary outcomes of interest are the rate of malignancy in patients who undergo colonic investigation after an admission for diverticulitis and the rate of non-malignant polyp detection found on colonic investigation following an admission diverticulitis.
Follow-up
All patients were followed up to a minimum of 24 months. The median time of follow up was 55.1 months. Clinical and electronic records were used to follow up patients, and will capture all endoscopic investigations in the Northland and Auckland regions.
Statistical analysis
Normally distributed data were presented as mean, standard deviation (SD) and tested with a student t-test. Categorical data were presented a number (n), percentage (%) and tested with a Chi-squared test. A binomial logistic regression was performed to investigate the factors associated with colonic investigation (colonoscopy or CT colonography). A p<0.05 was deemed significant. Statistical analysis was performed in SPSS for Mac.
Results
Patient characteristics
Four hundred and sixty-five patients were identified with diverticulitis during the study period. Forty-nine patients were excluded due to having colonic investigation in the past three years. Thirty-seven (8%) patients were excluded as they had a colonic resection during their index admission.
Three hundred and seventy-nine patients therefore formed the primary cohort: 97 (26%) with complicated disease and 282 (74%) with uncomplicated disease. Demographic characteristics are presented in Table 1.
View Tables 1–4.
The median age was 60 and 76 (20%) patients were Māori. There was no statistically significant difference in age or ethnicity between the two groups. A significantly higher proportion of male patients was seen in the complicated group with 58 (58%) of patients being male compared to 123 (44%) in the uncomplicated group.
Primary outcome
Overall, 182 (48%) patients underwent colonic investigation following an admission with diverticulitis; 50 (53%) in the complicated group and 132 (47%) in the uncomplicated group. Colonoscopy was more commonly performed compared to CTC as seen in Table 2.
Colonoscopy was performed in 170 (45%) patients and CTC in 18 (5%) of patients. Five patients had both colonoscopy and CTC. Four patients underwent a CTC due to inability to complete colonoscopy and in one patient it was unclear why they had both.
The acute presentation of diverticulitis was the reason for booking colonic investigation in all but two patients; both who had a change in bowel habit with concern for an underlying malignancy. Five patients (four with uncomplicated and one with complicated disease) had a plan made on discharge for colonoscopy that was not performed.
Secondary outcomes
Findings from colonic investigation are presented in Table 3.
A colonic malignancy was identified in two patients, both in the uncomplicated group. The CT scan reports of these two patients were reviewed in detail. There was no suggestion of malignancy on imaging. Benign strictures, colitis and haemorrhoids were uncommon findings and found in 3 (1.7%), 4 (2.2%), 3 (1.7%) patients, respectively.
Seventy-four polyps were found and resected in 61 patients (33.5%): 10 in the complicated group and 64 in the uncomplicated group. Low grade tubular adenomas and hyperplastic polyps were the most commonly found polyps, making up 42.9% and 41.6% of the polyps found respectively. Only two polyps were high grade tubular adenomas.
One patient with uncomplicated diverticulitis had a tubulovillous adenoma found in the caecum, and at repeat colonoscopy at one year was found to have a caecal adenocarcinoma.
No further malignancies were found on colonic investigation over the follow-up period.
Factors associated with colonic investigation
The performance of a colonic investigation was not associated with complicated disease, ethnicity, gender or age on univariate or multivariate analysis as seen in Table 4.
Discussion
This study demonstrated that colonic investigation following an admission for acute diverticulitis in Northland does not appear to be consistent with published guidelines. These guidelines[[9,10]] were, however, published later than the start of the data collection period for this study. Malignancy and polyp detection rate was higher in patients with uncomplicated disease, but remained low across the whole cohort. These data is important as an aid to formulating local guidelines and guiding use of hospital resource in a constrained environment.
Improvements in availability and resolution of CT imaging have resulted in it being used far more often to diagnose acute diverticulitis[[17]] and has led to more accurate diagnosis,[[18]] which may distinguish between diverticulitis and colorectal cancer. Multiple recent studies have questioned the need for follow up colonoscopy in those with uncomplicated disease due to developments in HR-CT, and the low rate of CRC seen in this group.[[19,20]]
The findings of this study are similar to those seen previously with regards to outcomes in patients with uncomplicated diverticulitis. Eight systematic reviews have investigated the role of colonic investigation following acute diverticulitis since 2012. The rate of CRC in those with uncomplicated diverticulitis in these reviews ranged from 0.5–2.1%.[[7,9,21–26]] Given the rate of CRC in those with uncomplicated diverticulitis being the same as those in a screening population, these reviews have questioned the need for colonic investigation in those with uncomplicated disease; however, none have made strong recommendations. Westwood et al.[[27]] provides the only New Zealand based data on colonic investigation following uncomplicated diverticulitis, from over ten years ago. In patients with uncomplicated diverticulitis a low rate of colonic malignancy (1.1%) was found.
In patients with complicated disease the pick-up rate in this study for both carcinoma and polyps was low. This is in contrast to four previous systematic reviews that have assessed malignancy rate following complicated diverticulitis where the rate ranged from 6.14–10.8%.[[7,9,25–26]] It should also be noted that although there was a significant proportion of patients who did not have colonic investigation arranged following admission (48%), at a median follow-up time of 55.1 months, none of these patients had represented to a hospital service with a new diagnosis of colorectal malignancy. It is possible that international data is not generalisable to a New Zealand population, but it is also likely that the increasing rate of diverticulitis and its detection in younger patients, coupled with easy access to improved imaging, has affected this.
The colonic investigation rate seen in the only New Zealand study was 70%, which is higher than that seen in Northland.[[27]] During our study colonic investigation following diverticulitis was an individual clinician decision with no hospital specific or New Zealand specific guidelines to aid decision making. The reason for the low investigation rate in patients with complicated disease is unclear but may include resource constraints, clinician decision making and patient factors or wishes.
The authors accept and acknowledge the limitations of this study. It is a single-centre retrospective study with a relatively small number of patients with complicated disease. The investigation rate was also low compared to previous local data. Patients were followed up with clinical records only, and those who had colonic investigation or malignancy diagnosed outside of the Northland Region were may have been missed. Patients who were discharged directly from ED were not included in this study. Despite this, it remains the largest study in New Zealand of colonic investigation following acute diverticulitis, and all patients were followed up for a minimum of two years to determine outcomes.
Conclusion
Colonic investigation following an admission for acute diverticulitis in Northland is not aligned with recently published guidelines. Rate of colonic malignancy on colonic investigation was low and no patients represented with a missed cancer diagnosis to a hospital service during the study follow-up. Larger studies and national guidance are needed to guide clinicians and maximise efficiency of resource utilisation.
Summary
Abstract
Aim
Diverticulitis is common and increasing in incidence. The risk of malignancy in those with uncomplicated diverticulitis is estimated to be 0.7%, compared with 10% in complicated diverticulitis. Newer guidelines suggest colonic investigation in patients with complicated diverticulitis only. We aim to investigate which patients in Northland undergo colonic investigation following an episode of diverticulitis, define malignancy detection rate and aid in the formulation of local guidelines.
Method
A retrospective review of adults admitted to Whangārei Hospital with diverticulitis between 2015 and 2019. Patients were classified as complicated or uncomplicated based on the Hinchey classification radiologically or intra-operatively. Patients were followed up to a minimum of 24 months.
Results
Three hundred and forty-nine patients were included. One hundred and eighty-two (48%) patients underwent colonic investigation following admission with diverticulitis; 50 with complicated and 132 with uncomplicated disease. The rate of colonic investigation between the groups was similar, at 53% and 47% respectively. Two patients(1.1%) were found to have a colonic malignancy, both in the uncomplicated group. The performance of a colonic investigation was not associated with complicated disease, ethnicity, gender or age on univariate or multivariate analysis.
Conclusion
Colonic investigation following an admission for acute diverticulitis in Northland is not aligned with recently published guidelines. The rate of colonic malignancy found was low. Larger local studies are needed to guide clinicians and maximise efficiency of resource utilisation.
Author Information
Acknowledgements
Correspondence
Correspondence Email
Competing Interests
1) Munie ST, Nalamati SPM. Epidemiology and Pathophysiology of Diverticular Disease. Clin Colon Rectal Surg. 2018 Jul; 31(4):209-213. doi: 10.1055/s-0037-1607464.
2) Nguyen GC, Sam J, Anand N. Epidemiological trends and geographic variation in hospital admissions for diverticulitis in the United States. World J Gastroenterol. 2011 Mar 28;17(12):1600-1605. doi: 10.3748/wjg.v17.i12.1600.
3) Granlund J, Sköldberg F, Hjern F, et al. Mortality in patients hospitalised for diverticulitis in Sweden—A national population-based cohort study. GastroHep. 2021;3:131-140. doi: 10.1002/ygh2.454.
4) Strate LL, Morris AM. Epidemiology, Pathophysiology, and Treatment of Diverticulitis. Gastroenterology. 2019 Apr;156(5):1282-1298.e1. doi: 10.1053/j.gastro.2018.12.033.
5) Wieghard, N., Geltzeiler, C. B., & Tsikitis, V. L. Trends in the surgical management of diverticulitis. Ann Gastroenterol. 2015 Jan-Mar;28(1):25-30.
6) Klarenbeek BR, de Korte N, van der Peet DL, Cuesta MA. Review of current classifications for diverticular disease and a translation into clinical practice. Int J Colorectal Dis. 2012 Feb;27(2):207-214. doi: 10.1007/s00384-011-1314-5.
7) Sharma PV, Eglinton T, Hider P, Frizelle F. Systematic review and meta-analysis of the role of routine colonic evaluation after radiologically confirmed acute diverticulitis. Ann Surg. 2014 Feb;259(2):263-272. doi: 10.1097/SLA.0000000000000294.
8) Stollman N, Smalley W, Hirano I; AGA Institute Clinical Guidelines Committee. American Gastroenterological Association Institute Guideline on the Management of Acute Diverticulitis. Gastroenterology. 2015 Dec;149(7):1944-1949. doi: 10.1053/j.gastro.2015.10.003.
9) Daniels L, Unlü C, de Wijkerslooth TR, Dekker E, Boermeester MA. Routine colonoscopy after left-sided acute uncomplicated diverticulitis: a systematic review. Gastrointest Endosc. 2014 Mar;79(3):378-498. quiz 498-498.e5. doi: 10.1016/j.gie.2013.11.013.
10) Francis NK, Sylla P, Abou-Khalil M, et al. EAES and SAGES 2018 consensus conference on acute diverticulitis management: evidence-based recommendations for clinical practice. Surg Endosc. 2019 Sep;33(9):2726-2741. doi: 10.1007/s00464-019-06882-z.
11) Schultz JK, Azhar N, Binda GA et al. European Society of Coloproctology: guidelines for the management of diverticular disease of the colon. Colorectal Dis. 2020 Sep,22 Suppl 2:5-28. doi: 10.1111/codi.15140.
12) Rottier SJ, van Dijk ST, van Geloven AAW et al. Meta-analysis of the role of colonoscopy after an episode of left-sided acute diverticulitis. Br J Surg 2019 Jul;106(8):988-97. doi: 10.1002/bjs.11191.
13) Meyer J, Orci LA, Combescure C et al. Risk of colorectal cancer in patients with acute diverticulitis: a systematic review and meta-analysis of observational studies. Clin Gastroenterol Hepatol 2019 Jul;17(8):1448-1456.e17. doi: 10.1016/j.cgh.2018.07.031.
14) World Health Organization [Internet] Geneva: Global Cancer Observatory: Cancer Today. 2018 [cited 10 July 2022]. Available from: https://gco.iarc.fr/.
15) Allemani C, Matsuda T, Di Carlo V et al, CONCORD Working Group. Global surveillance of trends in cancer survival 2000–14 (CONCORD-3): analysis of individual records for 37 513 025 patients diagnosed with one of 18 cancers from 322 population-based registries in 71 countries. Lancet. 2018 Mar 17;391(10125):1023-1075. doi: 10.1016/S0140-6736(17)33326-3.
16) Statistics New Zealand: New Zealand [Internet]. New Zealand; 2023. [cited 10 July 2022]. Subnational population estimates (RC, SA2), by age and sex, at 30 June 1996–2020 (2020 boundaries). Available from: https://nzdotstat.stats.govt.nz/wbos/Index.aspx?DataSetCode=TABLECODE7979.
17) Werner A, Diehl SJ, Farag-Soliman M, Düber C. Multi-slice spiral CT in routine diagnosis of suspected acute left-sided colonic diverticulitis: a prospective study of 120 patients. Eur Radiol. 2003 Dec;13(12):2596-2603. doi: 10.1007/s00330-003-1887-7.
18) Vather, R, Broad JB, Jaung R, Robertson J, Bissett IP. Demographics and trends in acute presentation of diverticular disease: a national study. ANZ J Surg. 2015 Oct;85(10):744-748. doi: 10.1111/ans.13147.
19) Díaz JJT, Asenjo BA, Soriano MR, Fernández CJ, Aurusa JOS, Rentería JPBH. Efficacy of colonoscopy after an episode of acute diverticulitis and risk of colorectal cancer. Ann Gastroenterol. 2020 Jan-Feb;33(1):68-72. doi: 10.20524/aog.2019.0437.
20) O’Donohoe N, Chandak P, Likos-Corbett M et al. Follow up colonoscopy may be omissible in uncomplicated left-sided acute diverticulitis diagnosed with CT- a retrospective cohort study. Sci Rep. 2019 Dec;9(1):20127. doi: 10.1038/s41598-019-56641-2.
21) Sai VF, Velayos F, Neuhaus J, Westphalen AC. Colonoscopy after CT diagnosis of diverticulitis to exclude colon cancer: a systematic literature review. Radiology. 2012 May; 263(2):383-390. doi: 10.1148/radiol.12111869. Erratum in: Radiology. 2012 Jul;264(1):306
22) Balk EM, Adam GP, Cao W, Mehta S, Shah N. Evaluation and Management After Acute Left-Sided Colonic Diverticulitis: A Systematic Review. Ann Intern Med. 2022 Mar;175(3):388-398. doi: 10.7326/M21-1646.
23) de Vries HS, Boerma D, Timmer R, van Ramshorst B, Dieleman LA, van Westreenen HL. Routine colonoscopy is not required in uncomplicated diverticulitis: a systematic review. Surg Endosc. 2014 Jul;28(7):2039-2047. doi: 10.1007/s00464-014-3447-4.
24) Koo CH, Chang JHE, Syn NL, Wee IJY, Mathew R. Systematic Review and Meta-analysis on Colorectal Cancer Findings on Colonic Evaluation After CT-Confirmed Acute Diverticulitis. Dis Colon Rectum. 2020 May;63(5):701-709. doi: 10.1097/DCR.0000000000001664.
25) Rottier SJ, van Dijk ST, van Geloven AAW, et al. Meta-analysis of the role of colonoscopy after an episode of left-sided acute diverticulitis. Br J Surg. 2019 Jul;106(8):988-997. doi: 10.1002/bjs.11191.
26) Meyer J, Orci LA, Combescure C, et al. Risk of Colorectal Cancer in Patients With Acute Diverticulitis: A Systematic Review and Meta-analysis of Observational Studies. Clin Gastroenterol Hepatol. 2019 Jul;17(8):1448-1456.e17. doi: 10.1016/j.cgh.2018.07.031.
27) Westwood DA, Eglinton TW, Frizelle FA. Routine colonoscopy following acute uncomplicated diverticulitis. Br J Surg. 2011 Nov;98(11):1630-1634. doi: 10.1002/bjs.7602.
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Colonic Investigation following acute diverticulitis in Northland, New Zealand
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Diverticular disease is extremely common in the Western world and is increasing in incidence, especially in younger patients.[[1]] Diverticulitis is a common manifestation of diverticular disease, and one of the commonest reasons for general surgical hospital admission.[[2]] It is associated with an increased mortality risk in patients at five years follow-up.[[3]] Treatment in hospital usually consists of intravenous antibiotic and supportive measures.[[4]] Occasional operative intervention is needed, but the majority of patients are discharged without undergoing colonic resection.[[5]]
Follow up, investigation and long-term management of these patients remains controversial, and is heavily dependent on resource availability.
Diverticulitis can be categorised as complicated or uncomplicated, which is determined radiologically with HR-CT (high resolution computed tomography) imaging.[[6]] In those with complicated diverticulitis, the rate of malignancy is estimated to be as high as 10%, compared to 0.7% in those with uncomplicated disease.[[7]] Historically, international guidelines including the American Gastroenterology Association (AGA)[[8]] guidelines, have suggested colonic investigation in all patients following resolution of acute diverticulitis; however, these recommendations are based on older data and expert opinion,[[9]] are likely to be outdated and do not take into account resource availability.
More recent guidelines from Society of American Gastrointestinal and Endoscopic Surgeons (SAGES)[[10]] and European Society of Coloproctology (ESC) recommend colonic investigation (colonoscopy or CT colonography) in patients with complicated diverticulitis only.[[11]] This is due to developments in CT imaging quality, and more recent meta-analyses that have shown the prevalence of colorectal cancer (CRC) in uncomplicated patients is low.[[12,13]] Interestingly although the overall rate of diverticulitis is increasing the prevalence of complicated disease has remained static.[[3]]
New Zealand has high rates of colonic cancer,[[14]] and worse outcomes compared to other countries.[[15]] There is also increasing pressure on endoscopy units throughout New Zealand, especially with bowel cancer screening being rolled out nationally. Decision making around selecting the most appropriate patients for whom to perform colonic investigation is therefore important in a resource constrained environment.
The aim of this study was to investigate which patients in Northland undergo colonic investigation following an episode of diverticulitis, define malignancy detection rate and aid in the formulation of local guidelines.
Methods
Setting
Whangārei Hospital is the largest hospital (249 beds) in Northland, New Zealand. It has the only General Surgical Unit in Northland, as well as the only hospital with CT and intensive care capability, and serves a population of 194,600.[[16]] During the study period there was no hospital policy regarding colonic investigation following an episode of diverticulitis. This decision was at the discretion of the treating clinician.
Study design
A retrospective study of all adults aged >18 who were admitted to Whangārei Hospital with diverticulitis between 1 January 2015 and 31 December 2019 was performed. Patients were identified using the International Classification of Disease, 10th revision code (see Appendix 1). Electronic medical records including emergency department (ED) notes, operation notes, and written clinical notes were interrogated to confirm inclusion criteria and record clinical outcomes. Baseline demographics, diverticulitis grading and complications, operative management and complications, length of stay, and 30-day, 90-day and 1-year readmission rates were collected.
Inclusion and exclusion criteria
Patients were excluded if aged younger than 18 years. The first presentation with diverticulitis during the study period was included with readmission data collected but not included as a separate case. Patients were excluded if a colonoscopy or CT colonography had been performed within three years.
Diverticulitis complexity
Patients were grouped into two groups based on the complexity of their diverticulitis. The Hinchey classification was used.[[6]] Uncomplicated diverticulitis was defined as Hinchey grade 1a and an absence of perforation, abscess or fistula. Hinchey Classification Grade was determined based on a CT report from a consultant radiologist or operative findings.
Outcomes of interest
The primary outcome of interest is rate of colonic investigation following admission for diverticulitis, according to diverticulitis severity grade. Secondary outcomes of interest are the rate of malignancy in patients who undergo colonic investigation after an admission for diverticulitis and the rate of non-malignant polyp detection found on colonic investigation following an admission diverticulitis.
Follow-up
All patients were followed up to a minimum of 24 months. The median time of follow up was 55.1 months. Clinical and electronic records were used to follow up patients, and will capture all endoscopic investigations in the Northland and Auckland regions.
Statistical analysis
Normally distributed data were presented as mean, standard deviation (SD) and tested with a student t-test. Categorical data were presented a number (n), percentage (%) and tested with a Chi-squared test. A binomial logistic regression was performed to investigate the factors associated with colonic investigation (colonoscopy or CT colonography). A p<0.05 was deemed significant. Statistical analysis was performed in SPSS for Mac.
Results
Patient characteristics
Four hundred and sixty-five patients were identified with diverticulitis during the study period. Forty-nine patients were excluded due to having colonic investigation in the past three years. Thirty-seven (8%) patients were excluded as they had a colonic resection during their index admission.
Three hundred and seventy-nine patients therefore formed the primary cohort: 97 (26%) with complicated disease and 282 (74%) with uncomplicated disease. Demographic characteristics are presented in Table 1.
View Tables 1–4.
The median age was 60 and 76 (20%) patients were Māori. There was no statistically significant difference in age or ethnicity between the two groups. A significantly higher proportion of male patients was seen in the complicated group with 58 (58%) of patients being male compared to 123 (44%) in the uncomplicated group.
Primary outcome
Overall, 182 (48%) patients underwent colonic investigation following an admission with diverticulitis; 50 (53%) in the complicated group and 132 (47%) in the uncomplicated group. Colonoscopy was more commonly performed compared to CTC as seen in Table 2.
Colonoscopy was performed in 170 (45%) patients and CTC in 18 (5%) of patients. Five patients had both colonoscopy and CTC. Four patients underwent a CTC due to inability to complete colonoscopy and in one patient it was unclear why they had both.
The acute presentation of diverticulitis was the reason for booking colonic investigation in all but two patients; both who had a change in bowel habit with concern for an underlying malignancy. Five patients (four with uncomplicated and one with complicated disease) had a plan made on discharge for colonoscopy that was not performed.
Secondary outcomes
Findings from colonic investigation are presented in Table 3.
A colonic malignancy was identified in two patients, both in the uncomplicated group. The CT scan reports of these two patients were reviewed in detail. There was no suggestion of malignancy on imaging. Benign strictures, colitis and haemorrhoids were uncommon findings and found in 3 (1.7%), 4 (2.2%), 3 (1.7%) patients, respectively.
Seventy-four polyps were found and resected in 61 patients (33.5%): 10 in the complicated group and 64 in the uncomplicated group. Low grade tubular adenomas and hyperplastic polyps were the most commonly found polyps, making up 42.9% and 41.6% of the polyps found respectively. Only two polyps were high grade tubular adenomas.
One patient with uncomplicated diverticulitis had a tubulovillous adenoma found in the caecum, and at repeat colonoscopy at one year was found to have a caecal adenocarcinoma.
No further malignancies were found on colonic investigation over the follow-up period.
Factors associated with colonic investigation
The performance of a colonic investigation was not associated with complicated disease, ethnicity, gender or age on univariate or multivariate analysis as seen in Table 4.
Discussion
This study demonstrated that colonic investigation following an admission for acute diverticulitis in Northland does not appear to be consistent with published guidelines. These guidelines[[9,10]] were, however, published later than the start of the data collection period for this study. Malignancy and polyp detection rate was higher in patients with uncomplicated disease, but remained low across the whole cohort. These data is important as an aid to formulating local guidelines and guiding use of hospital resource in a constrained environment.
Improvements in availability and resolution of CT imaging have resulted in it being used far more often to diagnose acute diverticulitis[[17]] and has led to more accurate diagnosis,[[18]] which may distinguish between diverticulitis and colorectal cancer. Multiple recent studies have questioned the need for follow up colonoscopy in those with uncomplicated disease due to developments in HR-CT, and the low rate of CRC seen in this group.[[19,20]]
The findings of this study are similar to those seen previously with regards to outcomes in patients with uncomplicated diverticulitis. Eight systematic reviews have investigated the role of colonic investigation following acute diverticulitis since 2012. The rate of CRC in those with uncomplicated diverticulitis in these reviews ranged from 0.5–2.1%.[[7,9,21–26]] Given the rate of CRC in those with uncomplicated diverticulitis being the same as those in a screening population, these reviews have questioned the need for colonic investigation in those with uncomplicated disease; however, none have made strong recommendations. Westwood et al.[[27]] provides the only New Zealand based data on colonic investigation following uncomplicated diverticulitis, from over ten years ago. In patients with uncomplicated diverticulitis a low rate of colonic malignancy (1.1%) was found.
In patients with complicated disease the pick-up rate in this study for both carcinoma and polyps was low. This is in contrast to four previous systematic reviews that have assessed malignancy rate following complicated diverticulitis where the rate ranged from 6.14–10.8%.[[7,9,25–26]] It should also be noted that although there was a significant proportion of patients who did not have colonic investigation arranged following admission (48%), at a median follow-up time of 55.1 months, none of these patients had represented to a hospital service with a new diagnosis of colorectal malignancy. It is possible that international data is not generalisable to a New Zealand population, but it is also likely that the increasing rate of diverticulitis and its detection in younger patients, coupled with easy access to improved imaging, has affected this.
The colonic investigation rate seen in the only New Zealand study was 70%, which is higher than that seen in Northland.[[27]] During our study colonic investigation following diverticulitis was an individual clinician decision with no hospital specific or New Zealand specific guidelines to aid decision making. The reason for the low investigation rate in patients with complicated disease is unclear but may include resource constraints, clinician decision making and patient factors or wishes.
The authors accept and acknowledge the limitations of this study. It is a single-centre retrospective study with a relatively small number of patients with complicated disease. The investigation rate was also low compared to previous local data. Patients were followed up with clinical records only, and those who had colonic investigation or malignancy diagnosed outside of the Northland Region were may have been missed. Patients who were discharged directly from ED were not included in this study. Despite this, it remains the largest study in New Zealand of colonic investigation following acute diverticulitis, and all patients were followed up for a minimum of two years to determine outcomes.
Conclusion
Colonic investigation following an admission for acute diverticulitis in Northland is not aligned with recently published guidelines. Rate of colonic malignancy on colonic investigation was low and no patients represented with a missed cancer diagnosis to a hospital service during the study follow-up. Larger studies and national guidance are needed to guide clinicians and maximise efficiency of resource utilisation.
Summary
Abstract
Aim
Diverticulitis is common and increasing in incidence. The risk of malignancy in those with uncomplicated diverticulitis is estimated to be 0.7%, compared with 10% in complicated diverticulitis. Newer guidelines suggest colonic investigation in patients with complicated diverticulitis only. We aim to investigate which patients in Northland undergo colonic investigation following an episode of diverticulitis, define malignancy detection rate and aid in the formulation of local guidelines.
Method
A retrospective review of adults admitted to Whangārei Hospital with diverticulitis between 2015 and 2019. Patients were classified as complicated or uncomplicated based on the Hinchey classification radiologically or intra-operatively. Patients were followed up to a minimum of 24 months.
Results
Three hundred and forty-nine patients were included. One hundred and eighty-two (48%) patients underwent colonic investigation following admission with diverticulitis; 50 with complicated and 132 with uncomplicated disease. The rate of colonic investigation between the groups was similar, at 53% and 47% respectively. Two patients(1.1%) were found to have a colonic malignancy, both in the uncomplicated group. The performance of a colonic investigation was not associated with complicated disease, ethnicity, gender or age on univariate or multivariate analysis.
Conclusion
Colonic investigation following an admission for acute diverticulitis in Northland is not aligned with recently published guidelines. The rate of colonic malignancy found was low. Larger local studies are needed to guide clinicians and maximise efficiency of resource utilisation.
Author Information
Acknowledgements
Correspondence
Correspondence Email
Competing Interests
1) Munie ST, Nalamati SPM. Epidemiology and Pathophysiology of Diverticular Disease. Clin Colon Rectal Surg. 2018 Jul; 31(4):209-213. doi: 10.1055/s-0037-1607464.
2) Nguyen GC, Sam J, Anand N. Epidemiological trends and geographic variation in hospital admissions for diverticulitis in the United States. World J Gastroenterol. 2011 Mar 28;17(12):1600-1605. doi: 10.3748/wjg.v17.i12.1600.
3) Granlund J, Sköldberg F, Hjern F, et al. Mortality in patients hospitalised for diverticulitis in Sweden—A national population-based cohort study. GastroHep. 2021;3:131-140. doi: 10.1002/ygh2.454.
4) Strate LL, Morris AM. Epidemiology, Pathophysiology, and Treatment of Diverticulitis. Gastroenterology. 2019 Apr;156(5):1282-1298.e1. doi: 10.1053/j.gastro.2018.12.033.
5) Wieghard, N., Geltzeiler, C. B., & Tsikitis, V. L. Trends in the surgical management of diverticulitis. Ann Gastroenterol. 2015 Jan-Mar;28(1):25-30.
6) Klarenbeek BR, de Korte N, van der Peet DL, Cuesta MA. Review of current classifications for diverticular disease and a translation into clinical practice. Int J Colorectal Dis. 2012 Feb;27(2):207-214. doi: 10.1007/s00384-011-1314-5.
7) Sharma PV, Eglinton T, Hider P, Frizelle F. Systematic review and meta-analysis of the role of routine colonic evaluation after radiologically confirmed acute diverticulitis. Ann Surg. 2014 Feb;259(2):263-272. doi: 10.1097/SLA.0000000000000294.
8) Stollman N, Smalley W, Hirano I; AGA Institute Clinical Guidelines Committee. American Gastroenterological Association Institute Guideline on the Management of Acute Diverticulitis. Gastroenterology. 2015 Dec;149(7):1944-1949. doi: 10.1053/j.gastro.2015.10.003.
9) Daniels L, Unlü C, de Wijkerslooth TR, Dekker E, Boermeester MA. Routine colonoscopy after left-sided acute uncomplicated diverticulitis: a systematic review. Gastrointest Endosc. 2014 Mar;79(3):378-498. quiz 498-498.e5. doi: 10.1016/j.gie.2013.11.013.
10) Francis NK, Sylla P, Abou-Khalil M, et al. EAES and SAGES 2018 consensus conference on acute diverticulitis management: evidence-based recommendations for clinical practice. Surg Endosc. 2019 Sep;33(9):2726-2741. doi: 10.1007/s00464-019-06882-z.
11) Schultz JK, Azhar N, Binda GA et al. European Society of Coloproctology: guidelines for the management of diverticular disease of the colon. Colorectal Dis. 2020 Sep,22 Suppl 2:5-28. doi: 10.1111/codi.15140.
12) Rottier SJ, van Dijk ST, van Geloven AAW et al. Meta-analysis of the role of colonoscopy after an episode of left-sided acute diverticulitis. Br J Surg 2019 Jul;106(8):988-97. doi: 10.1002/bjs.11191.
13) Meyer J, Orci LA, Combescure C et al. Risk of colorectal cancer in patients with acute diverticulitis: a systematic review and meta-analysis of observational studies. Clin Gastroenterol Hepatol 2019 Jul;17(8):1448-1456.e17. doi: 10.1016/j.cgh.2018.07.031.
14) World Health Organization [Internet] Geneva: Global Cancer Observatory: Cancer Today. 2018 [cited 10 July 2022]. Available from: https://gco.iarc.fr/.
15) Allemani C, Matsuda T, Di Carlo V et al, CONCORD Working Group. Global surveillance of trends in cancer survival 2000–14 (CONCORD-3): analysis of individual records for 37 513 025 patients diagnosed with one of 18 cancers from 322 population-based registries in 71 countries. Lancet. 2018 Mar 17;391(10125):1023-1075. doi: 10.1016/S0140-6736(17)33326-3.
16) Statistics New Zealand: New Zealand [Internet]. New Zealand; 2023. [cited 10 July 2022]. Subnational population estimates (RC, SA2), by age and sex, at 30 June 1996–2020 (2020 boundaries). Available from: https://nzdotstat.stats.govt.nz/wbos/Index.aspx?DataSetCode=TABLECODE7979.
17) Werner A, Diehl SJ, Farag-Soliman M, Düber C. Multi-slice spiral CT in routine diagnosis of suspected acute left-sided colonic diverticulitis: a prospective study of 120 patients. Eur Radiol. 2003 Dec;13(12):2596-2603. doi: 10.1007/s00330-003-1887-7.
18) Vather, R, Broad JB, Jaung R, Robertson J, Bissett IP. Demographics and trends in acute presentation of diverticular disease: a national study. ANZ J Surg. 2015 Oct;85(10):744-748. doi: 10.1111/ans.13147.
19) Díaz JJT, Asenjo BA, Soriano MR, Fernández CJ, Aurusa JOS, Rentería JPBH. Efficacy of colonoscopy after an episode of acute diverticulitis and risk of colorectal cancer. Ann Gastroenterol. 2020 Jan-Feb;33(1):68-72. doi: 10.20524/aog.2019.0437.
20) O’Donohoe N, Chandak P, Likos-Corbett M et al. Follow up colonoscopy may be omissible in uncomplicated left-sided acute diverticulitis diagnosed with CT- a retrospective cohort study. Sci Rep. 2019 Dec;9(1):20127. doi: 10.1038/s41598-019-56641-2.
21) Sai VF, Velayos F, Neuhaus J, Westphalen AC. Colonoscopy after CT diagnosis of diverticulitis to exclude colon cancer: a systematic literature review. Radiology. 2012 May; 263(2):383-390. doi: 10.1148/radiol.12111869. Erratum in: Radiology. 2012 Jul;264(1):306
22) Balk EM, Adam GP, Cao W, Mehta S, Shah N. Evaluation and Management After Acute Left-Sided Colonic Diverticulitis: A Systematic Review. Ann Intern Med. 2022 Mar;175(3):388-398. doi: 10.7326/M21-1646.
23) de Vries HS, Boerma D, Timmer R, van Ramshorst B, Dieleman LA, van Westreenen HL. Routine colonoscopy is not required in uncomplicated diverticulitis: a systematic review. Surg Endosc. 2014 Jul;28(7):2039-2047. doi: 10.1007/s00464-014-3447-4.
24) Koo CH, Chang JHE, Syn NL, Wee IJY, Mathew R. Systematic Review and Meta-analysis on Colorectal Cancer Findings on Colonic Evaluation After CT-Confirmed Acute Diverticulitis. Dis Colon Rectum. 2020 May;63(5):701-709. doi: 10.1097/DCR.0000000000001664.
25) Rottier SJ, van Dijk ST, van Geloven AAW, et al. Meta-analysis of the role of colonoscopy after an episode of left-sided acute diverticulitis. Br J Surg. 2019 Jul;106(8):988-997. doi: 10.1002/bjs.11191.
26) Meyer J, Orci LA, Combescure C, et al. Risk of Colorectal Cancer in Patients With Acute Diverticulitis: A Systematic Review and Meta-analysis of Observational Studies. Clin Gastroenterol Hepatol. 2019 Jul;17(8):1448-1456.e17. doi: 10.1016/j.cgh.2018.07.031.
27) Westwood DA, Eglinton TW, Frizelle FA. Routine colonoscopy following acute uncomplicated diverticulitis. Br J Surg. 2011 Nov;98(11):1630-1634. doi: 10.1002/bjs.7602.
For the PDF of this article,
contact nzmj@nzma.org.nz
Colonic Investigation following acute diverticulitis in Northland, New Zealand
View Article PDF
Diverticular disease is extremely common in the Western world and is increasing in incidence, especially in younger patients.[[1]] Diverticulitis is a common manifestation of diverticular disease, and one of the commonest reasons for general surgical hospital admission.[[2]] It is associated with an increased mortality risk in patients at five years follow-up.[[3]] Treatment in hospital usually consists of intravenous antibiotic and supportive measures.[[4]] Occasional operative intervention is needed, but the majority of patients are discharged without undergoing colonic resection.[[5]]
Follow up, investigation and long-term management of these patients remains controversial, and is heavily dependent on resource availability.
Diverticulitis can be categorised as complicated or uncomplicated, which is determined radiologically with HR-CT (high resolution computed tomography) imaging.[[6]] In those with complicated diverticulitis, the rate of malignancy is estimated to be as high as 10%, compared to 0.7% in those with uncomplicated disease.[[7]] Historically, international guidelines including the American Gastroenterology Association (AGA)[[8]] guidelines, have suggested colonic investigation in all patients following resolution of acute diverticulitis; however, these recommendations are based on older data and expert opinion,[[9]] are likely to be outdated and do not take into account resource availability.
More recent guidelines from Society of American Gastrointestinal and Endoscopic Surgeons (SAGES)[[10]] and European Society of Coloproctology (ESC) recommend colonic investigation (colonoscopy or CT colonography) in patients with complicated diverticulitis only.[[11]] This is due to developments in CT imaging quality, and more recent meta-analyses that have shown the prevalence of colorectal cancer (CRC) in uncomplicated patients is low.[[12,13]] Interestingly although the overall rate of diverticulitis is increasing the prevalence of complicated disease has remained static.[[3]]
New Zealand has high rates of colonic cancer,[[14]] and worse outcomes compared to other countries.[[15]] There is also increasing pressure on endoscopy units throughout New Zealand, especially with bowel cancer screening being rolled out nationally. Decision making around selecting the most appropriate patients for whom to perform colonic investigation is therefore important in a resource constrained environment.
The aim of this study was to investigate which patients in Northland undergo colonic investigation following an episode of diverticulitis, define malignancy detection rate and aid in the formulation of local guidelines.
Methods
Setting
Whangārei Hospital is the largest hospital (249 beds) in Northland, New Zealand. It has the only General Surgical Unit in Northland, as well as the only hospital with CT and intensive care capability, and serves a population of 194,600.[[16]] During the study period there was no hospital policy regarding colonic investigation following an episode of diverticulitis. This decision was at the discretion of the treating clinician.
Study design
A retrospective study of all adults aged >18 who were admitted to Whangārei Hospital with diverticulitis between 1 January 2015 and 31 December 2019 was performed. Patients were identified using the International Classification of Disease, 10th revision code (see Appendix 1). Electronic medical records including emergency department (ED) notes, operation notes, and written clinical notes were interrogated to confirm inclusion criteria and record clinical outcomes. Baseline demographics, diverticulitis grading and complications, operative management and complications, length of stay, and 30-day, 90-day and 1-year readmission rates were collected.
Inclusion and exclusion criteria
Patients were excluded if aged younger than 18 years. The first presentation with diverticulitis during the study period was included with readmission data collected but not included as a separate case. Patients were excluded if a colonoscopy or CT colonography had been performed within three years.
Diverticulitis complexity
Patients were grouped into two groups based on the complexity of their diverticulitis. The Hinchey classification was used.[[6]] Uncomplicated diverticulitis was defined as Hinchey grade 1a and an absence of perforation, abscess or fistula. Hinchey Classification Grade was determined based on a CT report from a consultant radiologist or operative findings.
Outcomes of interest
The primary outcome of interest is rate of colonic investigation following admission for diverticulitis, according to diverticulitis severity grade. Secondary outcomes of interest are the rate of malignancy in patients who undergo colonic investigation after an admission for diverticulitis and the rate of non-malignant polyp detection found on colonic investigation following an admission diverticulitis.
Follow-up
All patients were followed up to a minimum of 24 months. The median time of follow up was 55.1 months. Clinical and electronic records were used to follow up patients, and will capture all endoscopic investigations in the Northland and Auckland regions.
Statistical analysis
Normally distributed data were presented as mean, standard deviation (SD) and tested with a student t-test. Categorical data were presented a number (n), percentage (%) and tested with a Chi-squared test. A binomial logistic regression was performed to investigate the factors associated with colonic investigation (colonoscopy or CT colonography). A p<0.05 was deemed significant. Statistical analysis was performed in SPSS for Mac.
Results
Patient characteristics
Four hundred and sixty-five patients were identified with diverticulitis during the study period. Forty-nine patients were excluded due to having colonic investigation in the past three years. Thirty-seven (8%) patients were excluded as they had a colonic resection during their index admission.
Three hundred and seventy-nine patients therefore formed the primary cohort: 97 (26%) with complicated disease and 282 (74%) with uncomplicated disease. Demographic characteristics are presented in Table 1.
View Tables 1–4.
The median age was 60 and 76 (20%) patients were Māori. There was no statistically significant difference in age or ethnicity between the two groups. A significantly higher proportion of male patients was seen in the complicated group with 58 (58%) of patients being male compared to 123 (44%) in the uncomplicated group.
Primary outcome
Overall, 182 (48%) patients underwent colonic investigation following an admission with diverticulitis; 50 (53%) in the complicated group and 132 (47%) in the uncomplicated group. Colonoscopy was more commonly performed compared to CTC as seen in Table 2.
Colonoscopy was performed in 170 (45%) patients and CTC in 18 (5%) of patients. Five patients had both colonoscopy and CTC. Four patients underwent a CTC due to inability to complete colonoscopy and in one patient it was unclear why they had both.
The acute presentation of diverticulitis was the reason for booking colonic investigation in all but two patients; both who had a change in bowel habit with concern for an underlying malignancy. Five patients (four with uncomplicated and one with complicated disease) had a plan made on discharge for colonoscopy that was not performed.
Secondary outcomes
Findings from colonic investigation are presented in Table 3.
A colonic malignancy was identified in two patients, both in the uncomplicated group. The CT scan reports of these two patients were reviewed in detail. There was no suggestion of malignancy on imaging. Benign strictures, colitis and haemorrhoids were uncommon findings and found in 3 (1.7%), 4 (2.2%), 3 (1.7%) patients, respectively.
Seventy-four polyps were found and resected in 61 patients (33.5%): 10 in the complicated group and 64 in the uncomplicated group. Low grade tubular adenomas and hyperplastic polyps were the most commonly found polyps, making up 42.9% and 41.6% of the polyps found respectively. Only two polyps were high grade tubular adenomas.
One patient with uncomplicated diverticulitis had a tubulovillous adenoma found in the caecum, and at repeat colonoscopy at one year was found to have a caecal adenocarcinoma.
No further malignancies were found on colonic investigation over the follow-up period.
Factors associated with colonic investigation
The performance of a colonic investigation was not associated with complicated disease, ethnicity, gender or age on univariate or multivariate analysis as seen in Table 4.
Discussion
This study demonstrated that colonic investigation following an admission for acute diverticulitis in Northland does not appear to be consistent with published guidelines. These guidelines[[9,10]] were, however, published later than the start of the data collection period for this study. Malignancy and polyp detection rate was higher in patients with uncomplicated disease, but remained low across the whole cohort. These data is important as an aid to formulating local guidelines and guiding use of hospital resource in a constrained environment.
Improvements in availability and resolution of CT imaging have resulted in it being used far more often to diagnose acute diverticulitis[[17]] and has led to more accurate diagnosis,[[18]] which may distinguish between diverticulitis and colorectal cancer. Multiple recent studies have questioned the need for follow up colonoscopy in those with uncomplicated disease due to developments in HR-CT, and the low rate of CRC seen in this group.[[19,20]]
The findings of this study are similar to those seen previously with regards to outcomes in patients with uncomplicated diverticulitis. Eight systematic reviews have investigated the role of colonic investigation following acute diverticulitis since 2012. The rate of CRC in those with uncomplicated diverticulitis in these reviews ranged from 0.5–2.1%.[[7,9,21–26]] Given the rate of CRC in those with uncomplicated diverticulitis being the same as those in a screening population, these reviews have questioned the need for colonic investigation in those with uncomplicated disease; however, none have made strong recommendations. Westwood et al.[[27]] provides the only New Zealand based data on colonic investigation following uncomplicated diverticulitis, from over ten years ago. In patients with uncomplicated diverticulitis a low rate of colonic malignancy (1.1%) was found.
In patients with complicated disease the pick-up rate in this study for both carcinoma and polyps was low. This is in contrast to four previous systematic reviews that have assessed malignancy rate following complicated diverticulitis where the rate ranged from 6.14–10.8%.[[7,9,25–26]] It should also be noted that although there was a significant proportion of patients who did not have colonic investigation arranged following admission (48%), at a median follow-up time of 55.1 months, none of these patients had represented to a hospital service with a new diagnosis of colorectal malignancy. It is possible that international data is not generalisable to a New Zealand population, but it is also likely that the increasing rate of diverticulitis and its detection in younger patients, coupled with easy access to improved imaging, has affected this.
The colonic investigation rate seen in the only New Zealand study was 70%, which is higher than that seen in Northland.[[27]] During our study colonic investigation following diverticulitis was an individual clinician decision with no hospital specific or New Zealand specific guidelines to aid decision making. The reason for the low investigation rate in patients with complicated disease is unclear but may include resource constraints, clinician decision making and patient factors or wishes.
The authors accept and acknowledge the limitations of this study. It is a single-centre retrospective study with a relatively small number of patients with complicated disease. The investigation rate was also low compared to previous local data. Patients were followed up with clinical records only, and those who had colonic investigation or malignancy diagnosed outside of the Northland Region were may have been missed. Patients who were discharged directly from ED were not included in this study. Despite this, it remains the largest study in New Zealand of colonic investigation following acute diverticulitis, and all patients were followed up for a minimum of two years to determine outcomes.
Conclusion
Colonic investigation following an admission for acute diverticulitis in Northland is not aligned with recently published guidelines. Rate of colonic malignancy on colonic investigation was low and no patients represented with a missed cancer diagnosis to a hospital service during the study follow-up. Larger studies and national guidance are needed to guide clinicians and maximise efficiency of resource utilisation.
Summary
Abstract
Aim
Diverticulitis is common and increasing in incidence. The risk of malignancy in those with uncomplicated diverticulitis is estimated to be 0.7%, compared with 10% in complicated diverticulitis. Newer guidelines suggest colonic investigation in patients with complicated diverticulitis only. We aim to investigate which patients in Northland undergo colonic investigation following an episode of diverticulitis, define malignancy detection rate and aid in the formulation of local guidelines.
Method
A retrospective review of adults admitted to Whangārei Hospital with diverticulitis between 2015 and 2019. Patients were classified as complicated or uncomplicated based on the Hinchey classification radiologically or intra-operatively. Patients were followed up to a minimum of 24 months.
Results
Three hundred and forty-nine patients were included. One hundred and eighty-two (48%) patients underwent colonic investigation following admission with diverticulitis; 50 with complicated and 132 with uncomplicated disease. The rate of colonic investigation between the groups was similar, at 53% and 47% respectively. Two patients(1.1%) were found to have a colonic malignancy, both in the uncomplicated group. The performance of a colonic investigation was not associated with complicated disease, ethnicity, gender or age on univariate or multivariate analysis.
Conclusion
Colonic investigation following an admission for acute diverticulitis in Northland is not aligned with recently published guidelines. The rate of colonic malignancy found was low. Larger local studies are needed to guide clinicians and maximise efficiency of resource utilisation.
Author Information
Acknowledgements
Correspondence
Correspondence Email
Competing Interests
1) Munie ST, Nalamati SPM. Epidemiology and Pathophysiology of Diverticular Disease. Clin Colon Rectal Surg. 2018 Jul; 31(4):209-213. doi: 10.1055/s-0037-1607464.
2) Nguyen GC, Sam J, Anand N. Epidemiological trends and geographic variation in hospital admissions for diverticulitis in the United States. World J Gastroenterol. 2011 Mar 28;17(12):1600-1605. doi: 10.3748/wjg.v17.i12.1600.
3) Granlund J, Sköldberg F, Hjern F, et al. Mortality in patients hospitalised for diverticulitis in Sweden—A national population-based cohort study. GastroHep. 2021;3:131-140. doi: 10.1002/ygh2.454.
4) Strate LL, Morris AM. Epidemiology, Pathophysiology, and Treatment of Diverticulitis. Gastroenterology. 2019 Apr;156(5):1282-1298.e1. doi: 10.1053/j.gastro.2018.12.033.
5) Wieghard, N., Geltzeiler, C. B., & Tsikitis, V. L. Trends in the surgical management of diverticulitis. Ann Gastroenterol. 2015 Jan-Mar;28(1):25-30.
6) Klarenbeek BR, de Korte N, van der Peet DL, Cuesta MA. Review of current classifications for diverticular disease and a translation into clinical practice. Int J Colorectal Dis. 2012 Feb;27(2):207-214. doi: 10.1007/s00384-011-1314-5.
7) Sharma PV, Eglinton T, Hider P, Frizelle F. Systematic review and meta-analysis of the role of routine colonic evaluation after radiologically confirmed acute diverticulitis. Ann Surg. 2014 Feb;259(2):263-272. doi: 10.1097/SLA.0000000000000294.
8) Stollman N, Smalley W, Hirano I; AGA Institute Clinical Guidelines Committee. American Gastroenterological Association Institute Guideline on the Management of Acute Diverticulitis. Gastroenterology. 2015 Dec;149(7):1944-1949. doi: 10.1053/j.gastro.2015.10.003.
9) Daniels L, Unlü C, de Wijkerslooth TR, Dekker E, Boermeester MA. Routine colonoscopy after left-sided acute uncomplicated diverticulitis: a systematic review. Gastrointest Endosc. 2014 Mar;79(3):378-498. quiz 498-498.e5. doi: 10.1016/j.gie.2013.11.013.
10) Francis NK, Sylla P, Abou-Khalil M, et al. EAES and SAGES 2018 consensus conference on acute diverticulitis management: evidence-based recommendations for clinical practice. Surg Endosc. 2019 Sep;33(9):2726-2741. doi: 10.1007/s00464-019-06882-z.
11) Schultz JK, Azhar N, Binda GA et al. European Society of Coloproctology: guidelines for the management of diverticular disease of the colon. Colorectal Dis. 2020 Sep,22 Suppl 2:5-28. doi: 10.1111/codi.15140.
12) Rottier SJ, van Dijk ST, van Geloven AAW et al. Meta-analysis of the role of colonoscopy after an episode of left-sided acute diverticulitis. Br J Surg 2019 Jul;106(8):988-97. doi: 10.1002/bjs.11191.
13) Meyer J, Orci LA, Combescure C et al. Risk of colorectal cancer in patients with acute diverticulitis: a systematic review and meta-analysis of observational studies. Clin Gastroenterol Hepatol 2019 Jul;17(8):1448-1456.e17. doi: 10.1016/j.cgh.2018.07.031.
14) World Health Organization [Internet] Geneva: Global Cancer Observatory: Cancer Today. 2018 [cited 10 July 2022]. Available from: https://gco.iarc.fr/.
15) Allemani C, Matsuda T, Di Carlo V et al, CONCORD Working Group. Global surveillance of trends in cancer survival 2000–14 (CONCORD-3): analysis of individual records for 37 513 025 patients diagnosed with one of 18 cancers from 322 population-based registries in 71 countries. Lancet. 2018 Mar 17;391(10125):1023-1075. doi: 10.1016/S0140-6736(17)33326-3.
16) Statistics New Zealand: New Zealand [Internet]. New Zealand; 2023. [cited 10 July 2022]. Subnational population estimates (RC, SA2), by age and sex, at 30 June 1996–2020 (2020 boundaries). Available from: https://nzdotstat.stats.govt.nz/wbos/Index.aspx?DataSetCode=TABLECODE7979.
17) Werner A, Diehl SJ, Farag-Soliman M, Düber C. Multi-slice spiral CT in routine diagnosis of suspected acute left-sided colonic diverticulitis: a prospective study of 120 patients. Eur Radiol. 2003 Dec;13(12):2596-2603. doi: 10.1007/s00330-003-1887-7.
18) Vather, R, Broad JB, Jaung R, Robertson J, Bissett IP. Demographics and trends in acute presentation of diverticular disease: a national study. ANZ J Surg. 2015 Oct;85(10):744-748. doi: 10.1111/ans.13147.
19) Díaz JJT, Asenjo BA, Soriano MR, Fernández CJ, Aurusa JOS, Rentería JPBH. Efficacy of colonoscopy after an episode of acute diverticulitis and risk of colorectal cancer. Ann Gastroenterol. 2020 Jan-Feb;33(1):68-72. doi: 10.20524/aog.2019.0437.
20) O’Donohoe N, Chandak P, Likos-Corbett M et al. Follow up colonoscopy may be omissible in uncomplicated left-sided acute diverticulitis diagnosed with CT- a retrospective cohort study. Sci Rep. 2019 Dec;9(1):20127. doi: 10.1038/s41598-019-56641-2.
21) Sai VF, Velayos F, Neuhaus J, Westphalen AC. Colonoscopy after CT diagnosis of diverticulitis to exclude colon cancer: a systematic literature review. Radiology. 2012 May; 263(2):383-390. doi: 10.1148/radiol.12111869. Erratum in: Radiology. 2012 Jul;264(1):306
22) Balk EM, Adam GP, Cao W, Mehta S, Shah N. Evaluation and Management After Acute Left-Sided Colonic Diverticulitis: A Systematic Review. Ann Intern Med. 2022 Mar;175(3):388-398. doi: 10.7326/M21-1646.
23) de Vries HS, Boerma D, Timmer R, van Ramshorst B, Dieleman LA, van Westreenen HL. Routine colonoscopy is not required in uncomplicated diverticulitis: a systematic review. Surg Endosc. 2014 Jul;28(7):2039-2047. doi: 10.1007/s00464-014-3447-4.
24) Koo CH, Chang JHE, Syn NL, Wee IJY, Mathew R. Systematic Review and Meta-analysis on Colorectal Cancer Findings on Colonic Evaluation After CT-Confirmed Acute Diverticulitis. Dis Colon Rectum. 2020 May;63(5):701-709. doi: 10.1097/DCR.0000000000001664.
25) Rottier SJ, van Dijk ST, van Geloven AAW, et al. Meta-analysis of the role of colonoscopy after an episode of left-sided acute diverticulitis. Br J Surg. 2019 Jul;106(8):988-997. doi: 10.1002/bjs.11191.
26) Meyer J, Orci LA, Combescure C, et al. Risk of Colorectal Cancer in Patients With Acute Diverticulitis: A Systematic Review and Meta-analysis of Observational Studies. Clin Gastroenterol Hepatol. 2019 Jul;17(8):1448-1456.e17. doi: 10.1016/j.cgh.2018.07.031.
27) Westwood DA, Eglinton TW, Frizelle FA. Routine colonoscopy following acute uncomplicated diverticulitis. Br J Surg. 2011 Nov;98(11):1630-1634. doi: 10.1002/bjs.7602.
Contact diana@nzma.org.nz
for the PDF of this article
Colonic Investigation following acute diverticulitis in Northland, New Zealand
View Article PDF
Diverticular disease is extremely common in the Western world and is increasing in incidence, especially in younger patients.[[1]] Diverticulitis is a common manifestation of diverticular disease, and one of the commonest reasons for general surgical hospital admission.[[2]] It is associated with an increased mortality risk in patients at five years follow-up.[[3]] Treatment in hospital usually consists of intravenous antibiotic and supportive measures.[[4]] Occasional operative intervention is needed, but the majority of patients are discharged without undergoing colonic resection.[[5]]
Follow up, investigation and long-term management of these patients remains controversial, and is heavily dependent on resource availability.
Diverticulitis can be categorised as complicated or uncomplicated, which is determined radiologically with HR-CT (high resolution computed tomography) imaging.[[6]] In those with complicated diverticulitis, the rate of malignancy is estimated to be as high as 10%, compared to 0.7% in those with uncomplicated disease.[[7]] Historically, international guidelines including the American Gastroenterology Association (AGA)[[8]] guidelines, have suggested colonic investigation in all patients following resolution of acute diverticulitis; however, these recommendations are based on older data and expert opinion,[[9]] are likely to be outdated and do not take into account resource availability.
More recent guidelines from Society of American Gastrointestinal and Endoscopic Surgeons (SAGES)[[10]] and European Society of Coloproctology (ESC) recommend colonic investigation (colonoscopy or CT colonography) in patients with complicated diverticulitis only.[[11]] This is due to developments in CT imaging quality, and more recent meta-analyses that have shown the prevalence of colorectal cancer (CRC) in uncomplicated patients is low.[[12,13]] Interestingly although the overall rate of diverticulitis is increasing the prevalence of complicated disease has remained static.[[3]]
New Zealand has high rates of colonic cancer,[[14]] and worse outcomes compared to other countries.[[15]] There is also increasing pressure on endoscopy units throughout New Zealand, especially with bowel cancer screening being rolled out nationally. Decision making around selecting the most appropriate patients for whom to perform colonic investigation is therefore important in a resource constrained environment.
The aim of this study was to investigate which patients in Northland undergo colonic investigation following an episode of diverticulitis, define malignancy detection rate and aid in the formulation of local guidelines.
Methods
Setting
Whangārei Hospital is the largest hospital (249 beds) in Northland, New Zealand. It has the only General Surgical Unit in Northland, as well as the only hospital with CT and intensive care capability, and serves a population of 194,600.[[16]] During the study period there was no hospital policy regarding colonic investigation following an episode of diverticulitis. This decision was at the discretion of the treating clinician.
Study design
A retrospective study of all adults aged >18 who were admitted to Whangārei Hospital with diverticulitis between 1 January 2015 and 31 December 2019 was performed. Patients were identified using the International Classification of Disease, 10th revision code (see Appendix 1). Electronic medical records including emergency department (ED) notes, operation notes, and written clinical notes were interrogated to confirm inclusion criteria and record clinical outcomes. Baseline demographics, diverticulitis grading and complications, operative management and complications, length of stay, and 30-day, 90-day and 1-year readmission rates were collected.
Inclusion and exclusion criteria
Patients were excluded if aged younger than 18 years. The first presentation with diverticulitis during the study period was included with readmission data collected but not included as a separate case. Patients were excluded if a colonoscopy or CT colonography had been performed within three years.
Diverticulitis complexity
Patients were grouped into two groups based on the complexity of their diverticulitis. The Hinchey classification was used.[[6]] Uncomplicated diverticulitis was defined as Hinchey grade 1a and an absence of perforation, abscess or fistula. Hinchey Classification Grade was determined based on a CT report from a consultant radiologist or operative findings.
Outcomes of interest
The primary outcome of interest is rate of colonic investigation following admission for diverticulitis, according to diverticulitis severity grade. Secondary outcomes of interest are the rate of malignancy in patients who undergo colonic investigation after an admission for diverticulitis and the rate of non-malignant polyp detection found on colonic investigation following an admission diverticulitis.
Follow-up
All patients were followed up to a minimum of 24 months. The median time of follow up was 55.1 months. Clinical and electronic records were used to follow up patients, and will capture all endoscopic investigations in the Northland and Auckland regions.
Statistical analysis
Normally distributed data were presented as mean, standard deviation (SD) and tested with a student t-test. Categorical data were presented a number (n), percentage (%) and tested with a Chi-squared test. A binomial logistic regression was performed to investigate the factors associated with colonic investigation (colonoscopy or CT colonography). A p<0.05 was deemed significant. Statistical analysis was performed in SPSS for Mac.
Results
Patient characteristics
Four hundred and sixty-five patients were identified with diverticulitis during the study period. Forty-nine patients were excluded due to having colonic investigation in the past three years. Thirty-seven (8%) patients were excluded as they had a colonic resection during their index admission.
Three hundred and seventy-nine patients therefore formed the primary cohort: 97 (26%) with complicated disease and 282 (74%) with uncomplicated disease. Demographic characteristics are presented in Table 1.
View Tables 1–4.
The median age was 60 and 76 (20%) patients were Māori. There was no statistically significant difference in age or ethnicity between the two groups. A significantly higher proportion of male patients was seen in the complicated group with 58 (58%) of patients being male compared to 123 (44%) in the uncomplicated group.
Primary outcome
Overall, 182 (48%) patients underwent colonic investigation following an admission with diverticulitis; 50 (53%) in the complicated group and 132 (47%) in the uncomplicated group. Colonoscopy was more commonly performed compared to CTC as seen in Table 2.
Colonoscopy was performed in 170 (45%) patients and CTC in 18 (5%) of patients. Five patients had both colonoscopy and CTC. Four patients underwent a CTC due to inability to complete colonoscopy and in one patient it was unclear why they had both.
The acute presentation of diverticulitis was the reason for booking colonic investigation in all but two patients; both who had a change in bowel habit with concern for an underlying malignancy. Five patients (four with uncomplicated and one with complicated disease) had a plan made on discharge for colonoscopy that was not performed.
Secondary outcomes
Findings from colonic investigation are presented in Table 3.
A colonic malignancy was identified in two patients, both in the uncomplicated group. The CT scan reports of these two patients were reviewed in detail. There was no suggestion of malignancy on imaging. Benign strictures, colitis and haemorrhoids were uncommon findings and found in 3 (1.7%), 4 (2.2%), 3 (1.7%) patients, respectively.
Seventy-four polyps were found and resected in 61 patients (33.5%): 10 in the complicated group and 64 in the uncomplicated group. Low grade tubular adenomas and hyperplastic polyps were the most commonly found polyps, making up 42.9% and 41.6% of the polyps found respectively. Only two polyps were high grade tubular adenomas.
One patient with uncomplicated diverticulitis had a tubulovillous adenoma found in the caecum, and at repeat colonoscopy at one year was found to have a caecal adenocarcinoma.
No further malignancies were found on colonic investigation over the follow-up period.
Factors associated with colonic investigation
The performance of a colonic investigation was not associated with complicated disease, ethnicity, gender or age on univariate or multivariate analysis as seen in Table 4.
Discussion
This study demonstrated that colonic investigation following an admission for acute diverticulitis in Northland does not appear to be consistent with published guidelines. These guidelines[[9,10]] were, however, published later than the start of the data collection period for this study. Malignancy and polyp detection rate was higher in patients with uncomplicated disease, but remained low across the whole cohort. These data is important as an aid to formulating local guidelines and guiding use of hospital resource in a constrained environment.
Improvements in availability and resolution of CT imaging have resulted in it being used far more often to diagnose acute diverticulitis[[17]] and has led to more accurate diagnosis,[[18]] which may distinguish between diverticulitis and colorectal cancer. Multiple recent studies have questioned the need for follow up colonoscopy in those with uncomplicated disease due to developments in HR-CT, and the low rate of CRC seen in this group.[[19,20]]
The findings of this study are similar to those seen previously with regards to outcomes in patients with uncomplicated diverticulitis. Eight systematic reviews have investigated the role of colonic investigation following acute diverticulitis since 2012. The rate of CRC in those with uncomplicated diverticulitis in these reviews ranged from 0.5–2.1%.[[7,9,21–26]] Given the rate of CRC in those with uncomplicated diverticulitis being the same as those in a screening population, these reviews have questioned the need for colonic investigation in those with uncomplicated disease; however, none have made strong recommendations. Westwood et al.[[27]] provides the only New Zealand based data on colonic investigation following uncomplicated diverticulitis, from over ten years ago. In patients with uncomplicated diverticulitis a low rate of colonic malignancy (1.1%) was found.
In patients with complicated disease the pick-up rate in this study for both carcinoma and polyps was low. This is in contrast to four previous systematic reviews that have assessed malignancy rate following complicated diverticulitis where the rate ranged from 6.14–10.8%.[[7,9,25–26]] It should also be noted that although there was a significant proportion of patients who did not have colonic investigation arranged following admission (48%), at a median follow-up time of 55.1 months, none of these patients had represented to a hospital service with a new diagnosis of colorectal malignancy. It is possible that international data is not generalisable to a New Zealand population, but it is also likely that the increasing rate of diverticulitis and its detection in younger patients, coupled with easy access to improved imaging, has affected this.
The colonic investigation rate seen in the only New Zealand study was 70%, which is higher than that seen in Northland.[[27]] During our study colonic investigation following diverticulitis was an individual clinician decision with no hospital specific or New Zealand specific guidelines to aid decision making. The reason for the low investigation rate in patients with complicated disease is unclear but may include resource constraints, clinician decision making and patient factors or wishes.
The authors accept and acknowledge the limitations of this study. It is a single-centre retrospective study with a relatively small number of patients with complicated disease. The investigation rate was also low compared to previous local data. Patients were followed up with clinical records only, and those who had colonic investigation or malignancy diagnosed outside of the Northland Region were may have been missed. Patients who were discharged directly from ED were not included in this study. Despite this, it remains the largest study in New Zealand of colonic investigation following acute diverticulitis, and all patients were followed up for a minimum of two years to determine outcomes.
Conclusion
Colonic investigation following an admission for acute diverticulitis in Northland is not aligned with recently published guidelines. Rate of colonic malignancy on colonic investigation was low and no patients represented with a missed cancer diagnosis to a hospital service during the study follow-up. Larger studies and national guidance are needed to guide clinicians and maximise efficiency of resource utilisation.
Summary
Abstract
Aim
Diverticulitis is common and increasing in incidence. The risk of malignancy in those with uncomplicated diverticulitis is estimated to be 0.7%, compared with 10% in complicated diverticulitis. Newer guidelines suggest colonic investigation in patients with complicated diverticulitis only. We aim to investigate which patients in Northland undergo colonic investigation following an episode of diverticulitis, define malignancy detection rate and aid in the formulation of local guidelines.
Method
A retrospective review of adults admitted to Whangārei Hospital with diverticulitis between 2015 and 2019. Patients were classified as complicated or uncomplicated based on the Hinchey classification radiologically or intra-operatively. Patients were followed up to a minimum of 24 months.
Results
Three hundred and forty-nine patients were included. One hundred and eighty-two (48%) patients underwent colonic investigation following admission with diverticulitis; 50 with complicated and 132 with uncomplicated disease. The rate of colonic investigation between the groups was similar, at 53% and 47% respectively. Two patients(1.1%) were found to have a colonic malignancy, both in the uncomplicated group. The performance of a colonic investigation was not associated with complicated disease, ethnicity, gender or age on univariate or multivariate analysis.
Conclusion
Colonic investigation following an admission for acute diverticulitis in Northland is not aligned with recently published guidelines. The rate of colonic malignancy found was low. Larger local studies are needed to guide clinicians and maximise efficiency of resource utilisation.
Author Information
Acknowledgements
Correspondence
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Competing Interests
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Colonic Investigation following acute diverticulitis in Northland, New Zealand
Diverticulitis is a common manifestation of diverticular disease, and one of the commonest reasons for general surgical hospital admission.
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