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Diabetic retinopathy is a serious complication of diabetes and remains the leading cause of blindness among working-aged adults in the developed world.1 The progression of visual loss can be reduced with timely detection and treatment with laser photocoagulation.2,3National screening programmes are effective at detecting diabetic retinopathy and reducing visual impairment and blindness.4 In New Zealand, it has been estimated that approximately 30% of people with diabetes have retinopathy and 10% have disease that is sight threatening.5The Northland District Health Board (NDHB) services 3.6% of the national population. This equates to 159,160 people, making NDHB the tenth largest DHB in the country.6 NDHB services the fourth largest Mori population in New Zealand with 30% of Northland identifying as Mori.6 Sixty-three percent of Northland is European, 2.5% Pacific people (mostly of Samoan, Tongan, Niuean, or Cook Islands origin), and 4.5% Other.6NDHB has some of the highest levels of deprivation in the country.7 Over half of all Mori live in the most deprived quartile.7 One-third of Northlands population live in an urban Whangarei, with the remainder living in towns and rural areas across the district.8 Many communities are isolated and travel time is 5 hours from the most northern to southern extremities, and up to 2 hours east to west.8 A mobile screening programme for diabetic retinopathy was therefore essential to access all diabetics in Northland.Diabetic retinopathy screening in Northland started with direct ophthalmic examination by ophthalmologists at Whangarei Base Hospital. The Mobile Diabetic Retinopathy Screening Programme was quickly developed in response to the severity of initial retinopathy presentations.Mobile screening was launched in 1994, screened 450 patients over the year and consisted of one medical photographer driving to 8 different locations across Northland taking photographs with a conventional fundus camera. Films were then developed and all images were assessed by the author (Dr Dalziel), as secondary grader at Whangarei Base Hospital. The mobile screening service has since grown with the population of known diabetics and today runs 22 screening clinics in 14 regions, in collaboration with local providers.The aim of our study was to determine the prevalence of diabetic retinopathy and maculopathy in the Northland Diabetic Retinopathy Screening Programme.Method Research design The study accessed the Ophthalmology Digital Healthcare Database recently introduced in July 2011. This database recorded demographics, disease data and digital retinal photographs. All screening data from 10 February 2011 to 24 October 2012 was retrospectively assessed. The latest and most severe retinopathy and maculopathy grades of each patient were analysed. Screening centres Screening took place in 22 clinics in 14 regions including hospital outpatient clinics, medical centres, community centres and a correction facility. A qualified specialist medical photographer attended each venue and ran clinics in collaboration with local nurses. Data collection Data entered into the Ophthalmology Digital Healthcare Database were obtained through pre-screening questionnaires given to patients on arrival to each clinic. A local diabetic nurse double-checked answers, obtained visual acuity and consent, administered mydriatic drops (tropicamide 1% and phenylephrine 2.5%) and entered clinical data onto the database. After pre-assessment and mydriatic administration, a Zeiss ProNM camera was used to take three digital photographs, each with a 45 degree field of view in accordance with National Guidelines.5 Grading criteria Two grading systems were utilised in Northland. Initially, a local grading system was used that did not further define NPDR. In February 2012, this changed to the National Diabetes Retinal Screening Grading System.5 To enable analysis, data graded using the national guidelines were converted to the local grading system used prior to February 2012. Table 1 and Table 2 correlate the two grading systems. The primary and secondary graders consisted of a medical photographer and the designated ophthalmologist at Whangarei Base Hospital, respectively. For quality assurance purposes, 10 per cent of the primary graders images were reviewed by the latter in a random fashion. Patients were then sent written screening results and informed of their next appointment according to National Guideline Screening Intervals. Table 1. Correlation between Northland and national grading criteria for retinopathy5 Northland grade National grade Description Clinical signs Retinopathy NR R0 No retinopathy No abnormalities M-NPDR R1 Minimal <5 microaneurysms or dot haemorrhages NPDR R2 Mild >4 microaneurysms & dot haemorrhages Exudates>2DD from fovea R3 Moderate Any features of mild Blot or larger haemorrhages <1 quadrant of venous beading R4 Severe One or more of: \u2013 Definite IRMA \u2013 \u22652 quadrants venous beading \u2013 \u22652 quadrants blot or larger haemorrhages PDR R5 Proliferative One or more of: \u2013 Neovascularisation \u2013 Sub hyaloid or vitreous haemorrhage \u2013 Traction retinal detachment or Retinal Gliosis NR (No retinopathy); M-NPDR (Minimal Non Proliferative Diabetic Retinopathy); PDR (Proliferative Diabetic Retinopathy). Table 2. Correlation between Northland and national grading criteria for maculopathy5 Northland grade National grade Description Clinical signs Maculopathy No M M0 No maculopathy No abnormalities within 2DD of fovea M-NT M1 Minimal Microaneurysms & haemorrhages within 2DD but outside 1DD of fovea M2 Mild Microaneurysms & haemorrhages within 1DD No exudates or retinal thickening No reduction in vision M3 Mild Exudates (\u00b1 retinal thickening) within 2DD but outside 1DD M-T M4 Moderate Exudates or retinal thickening within 1DD Foveola not involved M5 Severe Exudates or retinal thickening involving the foveola. Reduced vision Note: No M (No maculopathy); M-NT (Maculopathy \u2013 No Treatment); M-T (Maculopathy \u2013 Treatment). Results Demographics From 10 February 2011 to 24 October 2012, a total of 7098 screens (14,197 retinal photographs) took place of 5647 diabetics. This represented approximately 77% of the diagnosed diabetes in the region.9 The latest grading of each patient was analysed. The two main ethnic groups were NZ European (56.5%) and Mori (39.3%). Age at screening ranged from 9 to 97 (mean\u00b1SD: 62.7\u00b113.7; median: 64; interquartile range: 18). Data for the number of years between the date of diabetes diagnosis and screening was missing in 41.7% of cases, with available data ranging from 0 to 71 years (11.0\u00b18.2; 10: 9). The mean failure-to-attend rate was 31%. The quality of retinal images was classed as good or adequate in 98.1%. The type of diabetes within the population ranged between Type 2 (n=2829; 88.7%), Type 1 (348; 6.4%), Other (7; 0.1%) and Maturity Onset Diabetes of the Young (MODY) (1; 0.0%). There were 262 cases with no diabetes type noted (4.8%). Retinopathy grading 81% of subjects had no retinopathy (Figure 1). A further 13.6% had minimal NPDR. The remaining 5.8% had either NPDR or PDR. Approximately 60 % of those with NPDR and 70% of those with PDR were screened outside of Whangarei. Figure 1. Prevalence of diabetic retinopathy in Northland Ethnicity data showed that 57% of those with NPDR were Mori. This corresponded to 7.8% of the total Mori population within the study. Fifty percent of the PDR population was Mori, corresponding to 0.5% of the studys Mori population (Table 3). Table 3. Distribution of retinopathy grading based on ethnicity Ethnicity NR (%) M-NPDR (%) NPDR (%) PDR (%) Grand total (%) European 2650 (83.0) 416 (13.0) 115 (3.6) 10 (0.3) 3191 (56.5) Mori 1729 (77.9) 307 (13.8) 173 (7.8) 11 (0.5) 2220 (39.3) Other 106 (76.3) 25 (18.0) 8 (5.8) 0 (0) 139 (2.5) Asian 33 (68.8) 10 (20.8) 4 (8.3) 1 (2.1) 48 (0.9) Pacific people 30 (71.4) 8 (19.0) 4 (9.5) 0 (0) 42 (0.7) Unidentified 7 (100) 0 (0) 0 (0)

Summary

Abstract

Aim

To determine the prevalence of diabetic retinopathy and maculopathy in the Northland Diabetic Retinopathy Screening Programme.

Method

Retrospective analysis of the latest and most severe retinopathy and maculopathy grades from each patient in the programme.

Results

Data from 7098 screenings from 5647 diabetics were obtained, which represented approximately 77% of the total number of diagnosed diabetics in Northland. The two main ethnic groups in our study were New Zealand European (56.5%) and Mori (39.3%). Retinopathy was present in 19% of the Northland diabetic screening population: 13.6% had minimal non-proliferative diabetic retinopathy (NPDR), 5.4% had NPDR and 0.4% had Proliferative Diabetic Retinopathy (PDR). Ethnicity data for NPDR was 57% Mori, 38% European, and PDR 50% Mori, 45% European. Maculopathy was present in 11%. Maculopathy requiring treatment was present in 1.4% (Mori 48%, European 44%). The mean failure-to-attend rate was 31%.

Conclusion

Rates of retinopathy and maculopathy detected by the Northland screening programme were comparable to rates reported in Waikato, lower than Wellington rates and lower than international averages. Mori were over-represented in patients with retinopathy and maculopathy, but underrepresented within the screening population. The success of this programme was undermined by the high failure-to-attend rate despite attempts to improve access.

Author Information

Alistair T Papalii-Curtin, Senior House Surgeon, Ophthalmology, Wellington Hospital, Wellington; David M Dalziel, Ophthalmologist and Clinical Director, Department of Ophthalmology, Whangarei Hospital, Whangarei, Northland

Acknowledgements

We are grateful to Blair Johnson (Data Analyst, NDHB), Barbara Miller (Operations Manager, Breast Screening and Retinal Screening, NDHB), and Dianne Vickers (Medical Photographer, NDHB) for their advice and helpful comments in preparing this manuscript.

Correspondence

Alistair Papalii-Curtin, C/o Wellington Hospital, Newtown, Wellington 6021, New Zealand.

Correspondence Email

Alistair.Papalii-Curtin@ccdhb.org.nz

Competing Interests

None identified.

Klein BE. Overview of epidemiologic studies of diabetic retinopathy. Ophthalmic Epidemiol. 2007;14:179-83.Hutchins E, Coppell KJ, Morris A, Sanderson G. Diabetic retinopathy screening in New Zealand requires improvement: results from a multi-centre audit. Aust N Z J Public Health. 2012;36(3):257-62.Giuliari GP. Diabetic Retinopathy: Current and New Treatment Options. Current Diabetes Reviews. 2012;8:32-41.James M, Turner DA, Broadbent DM, et al. Cost effectiveness analysis screening for sight threatening diabetic eye disease. BMJ. 2000;320:1627-31.Ministry of Health (MoH). National Diabetes Retinal Screening Grading System and Referral Guidelines 2006. Wellington: MoH, 2006.Statistics New Zealand. 2006 Census: District Health Board Area Summary. www.stats.govt.nz: Statistics New Zealand, 2006.Northland District Health Board (NDHB). Maori Health Annual Plan 2012/13. Northland: NDHB, 2012.Northland District Health Board (NDHB). Annual Plan 2012/13. Northland: NDHB, 2012.Northland Local Diabetes Team (NLDT). Local Diabetes Team Annual Report. Northland: NLDT, 2010.Ministry of Health (MoH). A portrait of health: key results of the 2006/2007 New Zealand Health Survey. Wellington: MoH, 2008.Joshy. G, Porter. T, Le Lievre. C, et al. Prevalence of diabetes in New Zealand general practice: the influence of ethnicity and social deprivation. Journal of Epidemiology & Community Health. 2009;63(5):386-90.Avery N, Chan K, Maslin K. Progression of diabetic maculopathy in patients on the Wellington Diabetic Screening Programme initially graded M3. N Z Med J. 2013;126(1372):32-6.Simmons D, Rush E, Crook N. Prevalence of undiagnosed diabetes, impaired glucose tolerance, and impaired fasting glucose among Maori in Te Wai o Rona: Diabetes Prevention Strategy. N Z Med J. 2009;122(1288):30-8.Frederikson LG, Jacobs RJ. Diabetes eye screening in the Wellington region of New Zealand: characteristics of the enrolled population (2002-2005). N Z Med J. 2008;121(1270):21-34.Reda E, Dunn P, Straker C, et al. Screening for diabetic retinopathy using the mobile retinal camera: the Waikato experience. N Z Med J. 2003;116(1180):U562.Mitchell P, Moffitt P. Update and implications from the Newcastle diabetic retinopathy study. Aust NZ J Ophthalmol. 1990;18:13-7.Yau JWY, Rogers SL, Kawasaki R, et al. Global prevalence and major risk factors of diabetic retinopathy. Diabetes Care. 2012;35:556-64.British Diabetic Association (BDA). Retinal photography screening for diabetic eye disease: a BDA report. London: BDA, 1997.Blundell R, Gibbons V, Lillis S. Cultural issues in research, a reflection. N Z Med J. 2010;123(1309):97-105.White B, Chamberlain N. Screening for diabetes, impaired glucose tolerance, and cardiovascular risk in primary care: a Northland, New Zealand pilot study. N Z Med J. 2009;122(1295):28-37.

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contact nzmj@nzma.org.nz

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Diabetic retinopathy is a serious complication of diabetes and remains the leading cause of blindness among working-aged adults in the developed world.1 The progression of visual loss can be reduced with timely detection and treatment with laser photocoagulation.2,3National screening programmes are effective at detecting diabetic retinopathy and reducing visual impairment and blindness.4 In New Zealand, it has been estimated that approximately 30% of people with diabetes have retinopathy and 10% have disease that is sight threatening.5The Northland District Health Board (NDHB) services 3.6% of the national population. This equates to 159,160 people, making NDHB the tenth largest DHB in the country.6 NDHB services the fourth largest Mori population in New Zealand with 30% of Northland identifying as Mori.6 Sixty-three percent of Northland is European, 2.5% Pacific people (mostly of Samoan, Tongan, Niuean, or Cook Islands origin), and 4.5% Other.6NDHB has some of the highest levels of deprivation in the country.7 Over half of all Mori live in the most deprived quartile.7 One-third of Northlands population live in an urban Whangarei, with the remainder living in towns and rural areas across the district.8 Many communities are isolated and travel time is 5 hours from the most northern to southern extremities, and up to 2 hours east to west.8 A mobile screening programme for diabetic retinopathy was therefore essential to access all diabetics in Northland.Diabetic retinopathy screening in Northland started with direct ophthalmic examination by ophthalmologists at Whangarei Base Hospital. The Mobile Diabetic Retinopathy Screening Programme was quickly developed in response to the severity of initial retinopathy presentations.Mobile screening was launched in 1994, screened 450 patients over the year and consisted of one medical photographer driving to 8 different locations across Northland taking photographs with a conventional fundus camera. Films were then developed and all images were assessed by the author (Dr Dalziel), as secondary grader at Whangarei Base Hospital. The mobile screening service has since grown with the population of known diabetics and today runs 22 screening clinics in 14 regions, in collaboration with local providers.The aim of our study was to determine the prevalence of diabetic retinopathy and maculopathy in the Northland Diabetic Retinopathy Screening Programme.Method Research design The study accessed the Ophthalmology Digital Healthcare Database recently introduced in July 2011. This database recorded demographics, disease data and digital retinal photographs. All screening data from 10 February 2011 to 24 October 2012 was retrospectively assessed. The latest and most severe retinopathy and maculopathy grades of each patient were analysed. Screening centres Screening took place in 22 clinics in 14 regions including hospital outpatient clinics, medical centres, community centres and a correction facility. A qualified specialist medical photographer attended each venue and ran clinics in collaboration with local nurses. Data collection Data entered into the Ophthalmology Digital Healthcare Database were obtained through pre-screening questionnaires given to patients on arrival to each clinic. A local diabetic nurse double-checked answers, obtained visual acuity and consent, administered mydriatic drops (tropicamide 1% and phenylephrine 2.5%) and entered clinical data onto the database. After pre-assessment and mydriatic administration, a Zeiss ProNM camera was used to take three digital photographs, each with a 45 degree field of view in accordance with National Guidelines.5 Grading criteria Two grading systems were utilised in Northland. Initially, a local grading system was used that did not further define NPDR. In February 2012, this changed to the National Diabetes Retinal Screening Grading System.5 To enable analysis, data graded using the national guidelines were converted to the local grading system used prior to February 2012. Table 1 and Table 2 correlate the two grading systems. The primary and secondary graders consisted of a medical photographer and the designated ophthalmologist at Whangarei Base Hospital, respectively. For quality assurance purposes, 10 per cent of the primary graders images were reviewed by the latter in a random fashion. Patients were then sent written screening results and informed of their next appointment according to National Guideline Screening Intervals. Table 1. Correlation between Northland and national grading criteria for retinopathy5 Northland grade National grade Description Clinical signs Retinopathy NR R0 No retinopathy No abnormalities M-NPDR R1 Minimal <5 microaneurysms or dot haemorrhages NPDR R2 Mild >4 microaneurysms & dot haemorrhages Exudates>2DD from fovea R3 Moderate Any features of mild Blot or larger haemorrhages <1 quadrant of venous beading R4 Severe One or more of: \u2013 Definite IRMA \u2013 \u22652 quadrants venous beading \u2013 \u22652 quadrants blot or larger haemorrhages PDR R5 Proliferative One or more of: \u2013 Neovascularisation \u2013 Sub hyaloid or vitreous haemorrhage \u2013 Traction retinal detachment or Retinal Gliosis NR (No retinopathy); M-NPDR (Minimal Non Proliferative Diabetic Retinopathy); PDR (Proliferative Diabetic Retinopathy). Table 2. Correlation between Northland and national grading criteria for maculopathy5 Northland grade National grade Description Clinical signs Maculopathy No M M0 No maculopathy No abnormalities within 2DD of fovea M-NT M1 Minimal Microaneurysms & haemorrhages within 2DD but outside 1DD of fovea M2 Mild Microaneurysms & haemorrhages within 1DD No exudates or retinal thickening No reduction in vision M3 Mild Exudates (\u00b1 retinal thickening) within 2DD but outside 1DD M-T M4 Moderate Exudates or retinal thickening within 1DD Foveola not involved M5 Severe Exudates or retinal thickening involving the foveola. Reduced vision Note: No M (No maculopathy); M-NT (Maculopathy \u2013 No Treatment); M-T (Maculopathy \u2013 Treatment). Results Demographics From 10 February 2011 to 24 October 2012, a total of 7098 screens (14,197 retinal photographs) took place of 5647 diabetics. This represented approximately 77% of the diagnosed diabetes in the region.9 The latest grading of each patient was analysed. The two main ethnic groups were NZ European (56.5%) and Mori (39.3%). Age at screening ranged from 9 to 97 (mean\u00b1SD: 62.7\u00b113.7; median: 64; interquartile range: 18). Data for the number of years between the date of diabetes diagnosis and screening was missing in 41.7% of cases, with available data ranging from 0 to 71 years (11.0\u00b18.2; 10: 9). The mean failure-to-attend rate was 31%. The quality of retinal images was classed as good or adequate in 98.1%. The type of diabetes within the population ranged between Type 2 (n=2829; 88.7%), Type 1 (348; 6.4%), Other (7; 0.1%) and Maturity Onset Diabetes of the Young (MODY) (1; 0.0%). There were 262 cases with no diabetes type noted (4.8%). Retinopathy grading 81% of subjects had no retinopathy (Figure 1). A further 13.6% had minimal NPDR. The remaining 5.8% had either NPDR or PDR. Approximately 60 % of those with NPDR and 70% of those with PDR were screened outside of Whangarei. Figure 1. Prevalence of diabetic retinopathy in Northland Ethnicity data showed that 57% of those with NPDR were Mori. This corresponded to 7.8% of the total Mori population within the study. Fifty percent of the PDR population was Mori, corresponding to 0.5% of the studys Mori population (Table 3). Table 3. Distribution of retinopathy grading based on ethnicity Ethnicity NR (%) M-NPDR (%) NPDR (%) PDR (%) Grand total (%) European 2650 (83.0) 416 (13.0) 115 (3.6) 10 (0.3) 3191 (56.5) Mori 1729 (77.9) 307 (13.8) 173 (7.8) 11 (0.5) 2220 (39.3) Other 106 (76.3) 25 (18.0) 8 (5.8) 0 (0) 139 (2.5) Asian 33 (68.8) 10 (20.8) 4 (8.3) 1 (2.1) 48 (0.9) Pacific people 30 (71.4) 8 (19.0) 4 (9.5) 0 (0) 42 (0.7) Unidentified 7 (100) 0 (0) 0 (0)

Summary

Abstract

Aim

To determine the prevalence of diabetic retinopathy and maculopathy in the Northland Diabetic Retinopathy Screening Programme.

Method

Retrospective analysis of the latest and most severe retinopathy and maculopathy grades from each patient in the programme.

Results

Data from 7098 screenings from 5647 diabetics were obtained, which represented approximately 77% of the total number of diagnosed diabetics in Northland. The two main ethnic groups in our study were New Zealand European (56.5%) and Mori (39.3%). Retinopathy was present in 19% of the Northland diabetic screening population: 13.6% had minimal non-proliferative diabetic retinopathy (NPDR), 5.4% had NPDR and 0.4% had Proliferative Diabetic Retinopathy (PDR). Ethnicity data for NPDR was 57% Mori, 38% European, and PDR 50% Mori, 45% European. Maculopathy was present in 11%. Maculopathy requiring treatment was present in 1.4% (Mori 48%, European 44%). The mean failure-to-attend rate was 31%.

Conclusion

Rates of retinopathy and maculopathy detected by the Northland screening programme were comparable to rates reported in Waikato, lower than Wellington rates and lower than international averages. Mori were over-represented in patients with retinopathy and maculopathy, but underrepresented within the screening population. The success of this programme was undermined by the high failure-to-attend rate despite attempts to improve access.

Author Information

Alistair T Papalii-Curtin, Senior House Surgeon, Ophthalmology, Wellington Hospital, Wellington; David M Dalziel, Ophthalmologist and Clinical Director, Department of Ophthalmology, Whangarei Hospital, Whangarei, Northland

Acknowledgements

We are grateful to Blair Johnson (Data Analyst, NDHB), Barbara Miller (Operations Manager, Breast Screening and Retinal Screening, NDHB), and Dianne Vickers (Medical Photographer, NDHB) for their advice and helpful comments in preparing this manuscript.

Correspondence

Alistair Papalii-Curtin, C/o Wellington Hospital, Newtown, Wellington 6021, New Zealand.

Correspondence Email

Alistair.Papalii-Curtin@ccdhb.org.nz

Competing Interests

None identified.

Klein BE. Overview of epidemiologic studies of diabetic retinopathy. Ophthalmic Epidemiol. 2007;14:179-83.Hutchins E, Coppell KJ, Morris A, Sanderson G. Diabetic retinopathy screening in New Zealand requires improvement: results from a multi-centre audit. Aust N Z J Public Health. 2012;36(3):257-62.Giuliari GP. Diabetic Retinopathy: Current and New Treatment Options. Current Diabetes Reviews. 2012;8:32-41.James M, Turner DA, Broadbent DM, et al. Cost effectiveness analysis screening for sight threatening diabetic eye disease. BMJ. 2000;320:1627-31.Ministry of Health (MoH). National Diabetes Retinal Screening Grading System and Referral Guidelines 2006. Wellington: MoH, 2006.Statistics New Zealand. 2006 Census: District Health Board Area Summary. www.stats.govt.nz: Statistics New Zealand, 2006.Northland District Health Board (NDHB). Maori Health Annual Plan 2012/13. Northland: NDHB, 2012.Northland District Health Board (NDHB). Annual Plan 2012/13. Northland: NDHB, 2012.Northland Local Diabetes Team (NLDT). Local Diabetes Team Annual Report. Northland: NLDT, 2010.Ministry of Health (MoH). A portrait of health: key results of the 2006/2007 New Zealand Health Survey. Wellington: MoH, 2008.Joshy. G, Porter. T, Le Lievre. C, et al. Prevalence of diabetes in New Zealand general practice: the influence of ethnicity and social deprivation. Journal of Epidemiology & Community Health. 2009;63(5):386-90.Avery N, Chan K, Maslin K. Progression of diabetic maculopathy in patients on the Wellington Diabetic Screening Programme initially graded M3. N Z Med J. 2013;126(1372):32-6.Simmons D, Rush E, Crook N. Prevalence of undiagnosed diabetes, impaired glucose tolerance, and impaired fasting glucose among Maori in Te Wai o Rona: Diabetes Prevention Strategy. N Z Med J. 2009;122(1288):30-8.Frederikson LG, Jacobs RJ. Diabetes eye screening in the Wellington region of New Zealand: characteristics of the enrolled population (2002-2005). N Z Med J. 2008;121(1270):21-34.Reda E, Dunn P, Straker C, et al. Screening for diabetic retinopathy using the mobile retinal camera: the Waikato experience. N Z Med J. 2003;116(1180):U562.Mitchell P, Moffitt P. Update and implications from the Newcastle diabetic retinopathy study. Aust NZ J Ophthalmol. 1990;18:13-7.Yau JWY, Rogers SL, Kawasaki R, et al. Global prevalence and major risk factors of diabetic retinopathy. Diabetes Care. 2012;35:556-64.British Diabetic Association (BDA). Retinal photography screening for diabetic eye disease: a BDA report. London: BDA, 1997.Blundell R, Gibbons V, Lillis S. Cultural issues in research, a reflection. N Z Med J. 2010;123(1309):97-105.White B, Chamberlain N. Screening for diabetes, impaired glucose tolerance, and cardiovascular risk in primary care: a Northland, New Zealand pilot study. N Z Med J. 2009;122(1295):28-37.

For the PDF of this article,
contact nzmj@nzma.org.nz

View Article PDF

Diabetic retinopathy is a serious complication of diabetes and remains the leading cause of blindness among working-aged adults in the developed world.1 The progression of visual loss can be reduced with timely detection and treatment with laser photocoagulation.2,3National screening programmes are effective at detecting diabetic retinopathy and reducing visual impairment and blindness.4 In New Zealand, it has been estimated that approximately 30% of people with diabetes have retinopathy and 10% have disease that is sight threatening.5The Northland District Health Board (NDHB) services 3.6% of the national population. This equates to 159,160 people, making NDHB the tenth largest DHB in the country.6 NDHB services the fourth largest Mori population in New Zealand with 30% of Northland identifying as Mori.6 Sixty-three percent of Northland is European, 2.5% Pacific people (mostly of Samoan, Tongan, Niuean, or Cook Islands origin), and 4.5% Other.6NDHB has some of the highest levels of deprivation in the country.7 Over half of all Mori live in the most deprived quartile.7 One-third of Northlands population live in an urban Whangarei, with the remainder living in towns and rural areas across the district.8 Many communities are isolated and travel time is 5 hours from the most northern to southern extremities, and up to 2 hours east to west.8 A mobile screening programme for diabetic retinopathy was therefore essential to access all diabetics in Northland.Diabetic retinopathy screening in Northland started with direct ophthalmic examination by ophthalmologists at Whangarei Base Hospital. The Mobile Diabetic Retinopathy Screening Programme was quickly developed in response to the severity of initial retinopathy presentations.Mobile screening was launched in 1994, screened 450 patients over the year and consisted of one medical photographer driving to 8 different locations across Northland taking photographs with a conventional fundus camera. Films were then developed and all images were assessed by the author (Dr Dalziel), as secondary grader at Whangarei Base Hospital. The mobile screening service has since grown with the population of known diabetics and today runs 22 screening clinics in 14 regions, in collaboration with local providers.The aim of our study was to determine the prevalence of diabetic retinopathy and maculopathy in the Northland Diabetic Retinopathy Screening Programme.Method Research design The study accessed the Ophthalmology Digital Healthcare Database recently introduced in July 2011. This database recorded demographics, disease data and digital retinal photographs. All screening data from 10 February 2011 to 24 October 2012 was retrospectively assessed. The latest and most severe retinopathy and maculopathy grades of each patient were analysed. Screening centres Screening took place in 22 clinics in 14 regions including hospital outpatient clinics, medical centres, community centres and a correction facility. A qualified specialist medical photographer attended each venue and ran clinics in collaboration with local nurses. Data collection Data entered into the Ophthalmology Digital Healthcare Database were obtained through pre-screening questionnaires given to patients on arrival to each clinic. A local diabetic nurse double-checked answers, obtained visual acuity and consent, administered mydriatic drops (tropicamide 1% and phenylephrine 2.5%) and entered clinical data onto the database. After pre-assessment and mydriatic administration, a Zeiss ProNM camera was used to take three digital photographs, each with a 45 degree field of view in accordance with National Guidelines.5 Grading criteria Two grading systems were utilised in Northland. Initially, a local grading system was used that did not further define NPDR. In February 2012, this changed to the National Diabetes Retinal Screening Grading System.5 To enable analysis, data graded using the national guidelines were converted to the local grading system used prior to February 2012. Table 1 and Table 2 correlate the two grading systems. The primary and secondary graders consisted of a medical photographer and the designated ophthalmologist at Whangarei Base Hospital, respectively. For quality assurance purposes, 10 per cent of the primary graders images were reviewed by the latter in a random fashion. Patients were then sent written screening results and informed of their next appointment according to National Guideline Screening Intervals. Table 1. Correlation between Northland and national grading criteria for retinopathy5 Northland grade National grade Description Clinical signs Retinopathy NR R0 No retinopathy No abnormalities M-NPDR R1 Minimal <5 microaneurysms or dot haemorrhages NPDR R2 Mild >4 microaneurysms & dot haemorrhages Exudates>2DD from fovea R3 Moderate Any features of mild Blot or larger haemorrhages <1 quadrant of venous beading R4 Severe One or more of: \u2013 Definite IRMA \u2013 \u22652 quadrants venous beading \u2013 \u22652 quadrants blot or larger haemorrhages PDR R5 Proliferative One or more of: \u2013 Neovascularisation \u2013 Sub hyaloid or vitreous haemorrhage \u2013 Traction retinal detachment or Retinal Gliosis NR (No retinopathy); M-NPDR (Minimal Non Proliferative Diabetic Retinopathy); PDR (Proliferative Diabetic Retinopathy). Table 2. Correlation between Northland and national grading criteria for maculopathy5 Northland grade National grade Description Clinical signs Maculopathy No M M0 No maculopathy No abnormalities within 2DD of fovea M-NT M1 Minimal Microaneurysms & haemorrhages within 2DD but outside 1DD of fovea M2 Mild Microaneurysms & haemorrhages within 1DD No exudates or retinal thickening No reduction in vision M3 Mild Exudates (\u00b1 retinal thickening) within 2DD but outside 1DD M-T M4 Moderate Exudates or retinal thickening within 1DD Foveola not involved M5 Severe Exudates or retinal thickening involving the foveola. Reduced vision Note: No M (No maculopathy); M-NT (Maculopathy \u2013 No Treatment); M-T (Maculopathy \u2013 Treatment). Results Demographics From 10 February 2011 to 24 October 2012, a total of 7098 screens (14,197 retinal photographs) took place of 5647 diabetics. This represented approximately 77% of the diagnosed diabetes in the region.9 The latest grading of each patient was analysed. The two main ethnic groups were NZ European (56.5%) and Mori (39.3%). Age at screening ranged from 9 to 97 (mean\u00b1SD: 62.7\u00b113.7; median: 64; interquartile range: 18). Data for the number of years between the date of diabetes diagnosis and screening was missing in 41.7% of cases, with available data ranging from 0 to 71 years (11.0\u00b18.2; 10: 9). The mean failure-to-attend rate was 31%. The quality of retinal images was classed as good or adequate in 98.1%. The type of diabetes within the population ranged between Type 2 (n=2829; 88.7%), Type 1 (348; 6.4%), Other (7; 0.1%) and Maturity Onset Diabetes of the Young (MODY) (1; 0.0%). There were 262 cases with no diabetes type noted (4.8%). Retinopathy grading 81% of subjects had no retinopathy (Figure 1). A further 13.6% had minimal NPDR. The remaining 5.8% had either NPDR or PDR. Approximately 60 % of those with NPDR and 70% of those with PDR were screened outside of Whangarei. Figure 1. Prevalence of diabetic retinopathy in Northland Ethnicity data showed that 57% of those with NPDR were Mori. This corresponded to 7.8% of the total Mori population within the study. Fifty percent of the PDR population was Mori, corresponding to 0.5% of the studys Mori population (Table 3). Table 3. Distribution of retinopathy grading based on ethnicity Ethnicity NR (%) M-NPDR (%) NPDR (%) PDR (%) Grand total (%) European 2650 (83.0) 416 (13.0) 115 (3.6) 10 (0.3) 3191 (56.5) Mori 1729 (77.9) 307 (13.8) 173 (7.8) 11 (0.5) 2220 (39.3) Other 106 (76.3) 25 (18.0) 8 (5.8) 0 (0) 139 (2.5) Asian 33 (68.8) 10 (20.8) 4 (8.3) 1 (2.1) 48 (0.9) Pacific people 30 (71.4) 8 (19.0) 4 (9.5) 0 (0) 42 (0.7) Unidentified 7 (100) 0 (0) 0 (0)

Summary

Abstract

Aim

To determine the prevalence of diabetic retinopathy and maculopathy in the Northland Diabetic Retinopathy Screening Programme.

Method

Retrospective analysis of the latest and most severe retinopathy and maculopathy grades from each patient in the programme.

Results

Data from 7098 screenings from 5647 diabetics were obtained, which represented approximately 77% of the total number of diagnosed diabetics in Northland. The two main ethnic groups in our study were New Zealand European (56.5%) and Mori (39.3%). Retinopathy was present in 19% of the Northland diabetic screening population: 13.6% had minimal non-proliferative diabetic retinopathy (NPDR), 5.4% had NPDR and 0.4% had Proliferative Diabetic Retinopathy (PDR). Ethnicity data for NPDR was 57% Mori, 38% European, and PDR 50% Mori, 45% European. Maculopathy was present in 11%. Maculopathy requiring treatment was present in 1.4% (Mori 48%, European 44%). The mean failure-to-attend rate was 31%.

Conclusion

Rates of retinopathy and maculopathy detected by the Northland screening programme were comparable to rates reported in Waikato, lower than Wellington rates and lower than international averages. Mori were over-represented in patients with retinopathy and maculopathy, but underrepresented within the screening population. The success of this programme was undermined by the high failure-to-attend rate despite attempts to improve access.

Author Information

Alistair T Papalii-Curtin, Senior House Surgeon, Ophthalmology, Wellington Hospital, Wellington; David M Dalziel, Ophthalmologist and Clinical Director, Department of Ophthalmology, Whangarei Hospital, Whangarei, Northland

Acknowledgements

We are grateful to Blair Johnson (Data Analyst, NDHB), Barbara Miller (Operations Manager, Breast Screening and Retinal Screening, NDHB), and Dianne Vickers (Medical Photographer, NDHB) for their advice and helpful comments in preparing this manuscript.

Correspondence

Alistair Papalii-Curtin, C/o Wellington Hospital, Newtown, Wellington 6021, New Zealand.

Correspondence Email

Alistair.Papalii-Curtin@ccdhb.org.nz

Competing Interests

None identified.

Klein BE. Overview of epidemiologic studies of diabetic retinopathy. Ophthalmic Epidemiol. 2007;14:179-83.Hutchins E, Coppell KJ, Morris A, Sanderson G. Diabetic retinopathy screening in New Zealand requires improvement: results from a multi-centre audit. Aust N Z J Public Health. 2012;36(3):257-62.Giuliari GP. Diabetic Retinopathy: Current and New Treatment Options. Current Diabetes Reviews. 2012;8:32-41.James M, Turner DA, Broadbent DM, et al. Cost effectiveness analysis screening for sight threatening diabetic eye disease. BMJ. 2000;320:1627-31.Ministry of Health (MoH). National Diabetes Retinal Screening Grading System and Referral Guidelines 2006. Wellington: MoH, 2006.Statistics New Zealand. 2006 Census: District Health Board Area Summary. www.stats.govt.nz: Statistics New Zealand, 2006.Northland District Health Board (NDHB). Maori Health Annual Plan 2012/13. Northland: NDHB, 2012.Northland District Health Board (NDHB). Annual Plan 2012/13. Northland: NDHB, 2012.Northland Local Diabetes Team (NLDT). Local Diabetes Team Annual Report. Northland: NLDT, 2010.Ministry of Health (MoH). A portrait of health: key results of the 2006/2007 New Zealand Health Survey. Wellington: MoH, 2008.Joshy. G, Porter. T, Le Lievre. C, et al. Prevalence of diabetes in New Zealand general practice: the influence of ethnicity and social deprivation. Journal of Epidemiology & Community Health. 2009;63(5):386-90.Avery N, Chan K, Maslin K. Progression of diabetic maculopathy in patients on the Wellington Diabetic Screening Programme initially graded M3. N Z Med J. 2013;126(1372):32-6.Simmons D, Rush E, Crook N. Prevalence of undiagnosed diabetes, impaired glucose tolerance, and impaired fasting glucose among Maori in Te Wai o Rona: Diabetes Prevention Strategy. N Z Med J. 2009;122(1288):30-8.Frederikson LG, Jacobs RJ. Diabetes eye screening in the Wellington region of New Zealand: characteristics of the enrolled population (2002-2005). N Z Med J. 2008;121(1270):21-34.Reda E, Dunn P, Straker C, et al. Screening for diabetic retinopathy using the mobile retinal camera: the Waikato experience. N Z Med J. 2003;116(1180):U562.Mitchell P, Moffitt P. Update and implications from the Newcastle diabetic retinopathy study. Aust NZ J Ophthalmol. 1990;18:13-7.Yau JWY, Rogers SL, Kawasaki R, et al. Global prevalence and major risk factors of diabetic retinopathy. Diabetes Care. 2012;35:556-64.British Diabetic Association (BDA). Retinal photography screening for diabetic eye disease: a BDA report. London: BDA, 1997.Blundell R, Gibbons V, Lillis S. Cultural issues in research, a reflection. N Z Med J. 2010;123(1309):97-105.White B, Chamberlain N. Screening for diabetes, impaired glucose tolerance, and cardiovascular risk in primary care: a Northland, New Zealand pilot study. N Z Med J. 2009;122(1295):28-37.

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