Studies since the 1990s have consistently shown that Pacific peoples in New Zealand have higher incidence, mortality and case-fatality rates from cardiovascular diseases (CVD) than New Zealand Europeans.1-4 Research also suggests that these outcomes are the result of a more adverse CVD risk factor profile among Pacific peoples compared to Europeans.5-10 However, Pacific peoples in New Zealand are not a homogeneous population. The term ‘Pacific peoples' is an umbrella term describing about 7% of the New Zealand population who identify with at least one of the ethnic groups originating from the Pacific Islands of Polynesia, Melanesia and Micronesia.11 There are over 12 nations represented in New Zealand's Pacific community. However most Pacific peoples identify with one or more of the four main ethnic groups (Samoan, Tongan, Cook Island Māori and Niuean).12 Most health-related surveys present aggregated data from these different Pacific ethnic groups, in part because of the small samples of each contributing ethnic group. Research into CVD has been no exception. Despite recommendations to investigate each Pacific ethnic group separately,13-15 only two previous studies have attempted ethnic-specific analyses of the CVD risk profiles of Pacific peoples in New Zealand, and both studies only had the statistical power to find substantial differences between Pacific groups.13,16 Also of note, the New Zealand Census Mortality Study (NZCMS) reported much higher CVD mortality among Cook Island Māori (RR 1.66 compared with Samoans), which was reproduced in both 1991-99 and 2001-04 cohorts.15 This mortality differential is unexplained. PREDICT is a clinical decision support programme aimed at assisting primary care practitioners with CVD risk assessment and management.17 Since 2002, it has been implemented in nine PHOs throughout Auckland and Northland, representing about 65% of the population in these two regions. Over 10,000 Pacific participants have now been recruited into the PREDICT programme, which has generated the largest Pacific cohort ever assembled in New Zealand. This cohort does not currently include a representative sample of people living in New Zealand as only about 20% of the eligible population have been risk assessed to date. However it seems unlikely that there would be any systematic differences in the selection of patients from different Pacific groups for CVD risk assessment. Therefore, we present a comparative analysis of CVD risk factor profiles in the major Pacific populations living in New Zealand. While the ethnic-specific risk factor profiles reported here do not represent prevalence estimates for the Pacific populations in New Zealand, the PREDICT study provides an opportunity to add to our very limited knowledge on CVD risk factor differences between Pacific populations. Comparing these risk profiles could help answer the question "Is it appropriate to aggregate data on CVD risk profiles from different Pacific ethnic groups living in New Zealand?" Methods PREDICT is a web-based clinical decision support programme for CVD risk assessment and management in routine primary care practice. Study methods and data definitions are described in full elsewhere.17 The software programme has been integrated with several of the most commonly used primary care patient management systems. This integration allows uniform, systematically coded CVD risk data to be automatically (and anonymously) extracted from a patient's electronic medical record. Gaps in the data required to undertake a formal CVD risk assessment are then completed by either the GP or practice nurse on the PREDICT templates, which are then automatically written back to the patient medical record. Health data captured by PREDICT, including history of CVD, family history of CVD, and total cholesterol/HDL ratio, have previously been shown to be highly consistent with data held in electronic patient records.18 Risk profiles are sent via a secure broadband internet connection to a central server at the time of the assessment. Within seconds the clinician receives the patient's calculated 5-year CVD risk as well risk management recommendations based on New Zealand CVD risk management guidelines.19 The central server stores the CVD risk factor profiles of each patient, and with permission from participating PHOs, these are extracted anonymously and linked, via an encrypted National Health Index (NHI) number, to national hospitalisation and mortality datasets. PREDICT data can also be linked to the New Zealand Health Information Service (NZHIS) NHI dataset that holds details of date of birth, gender, ethnicity and socioeconomic status according to the NZDep01 Deprivation index. Ethnicity data can therefore be collected from the PREDICT template (originally from the patient's electronic medical record, or entered manually by the practitioner) or via linkage to the NHI dataset. Both datasets have provision for up to three different ethnicities to be entered, so that each patient in the PREDICT cohort could potentially have up to six ethnicities. Any person in the PREDICT cohort aged 35-74 years with a Pacific ethnicity on any one of the six potential ethnicity fields was included in these analyses. Pacific ethnicities were defined according to the Ministry of Health's Ethnicity Data Protocols for the Health and Disability Sector as Level 2 codes 30 to 37.20 However, preliminary analyses revealed that the Fijian group (code 36) was an anomaly, making up over 11% of the total Pacific cohort but only 4% of Pacific peoples in official New Zealand statistics.12 Furthermore, as the CVD risk profile of the Fijian group was much closer to that of the Indian cohort than to that of the other Pacific groups,21 we suspected that some of those classified as Fijians were not ethnic Fijians, but rather Fijian Indians. Therefore this group (n=1341) was excluded from these analyses. The Pacific groups included in this study were thus the level 2 ethnicity codes 31 (Samoan), 32 (Cook Island Māori), 33 (Tongan), 34 (Niuean), and a combined group of both codes 37 (Other Pacific peoples, including Tokelauans) and code 30 (Pacific peoples Not Further Defined, NFD). Less than 1% of patients in the Pacific cohort identified with more than one Pacific ethnicity. Classification of ethnicity prioritised the smaller Pacific groups over the larger ones, as was done in the 2001 New Zealand Census22 and the Diabetes, Heart and Health Study 2002/03.16This method gave first priority to Niuean, followed by Cook Island Māori, Tongan and lastly Samoan ethnicity. Only 70 people (0.7% of the Pacific cohort) identified themselves as Tokelauan (code 35), therefore they were included in the ‘Other Pacific peoples' ethnic group (code 37). The data extracts for these analyses included all PREDICT first risk assessments from August 2002 until January 2009. Data were analysed using Stata v10.0 statistical software. Men and women were analysed separately. Deprivation was assessed according to the NZDep01 index. NZDep01 is a census based small area index of deprivation, which assigns a relative deprivation score to each meshblock in New Zealand.23 Each individual was assigned the value according to their meshblock of residence. Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated for each ethnic group with Samoans as the reference group, as they comprised the largest group, making up almost 50% of the Pacific cohort. A binomial regression model was used to calculate risk ratios (RR) adjusted for age. A post-regression test was used to test for any overall differences in proportions between groups. A linear regression model adjusting for age was used to calculate mean differences and 95% CIs for continuous CVD risk factor data, again with Samoans as the reference group. Mean differences in Framingham risk scores were also calculated, using the original Framingham risk prediction equation24 rather than the New Zealand Guidelines Group-adjusted Framingham equation which adds a 5% 5 year risk increment to high risk ethnic groups including Pacific peoples.19 We decided not to adjust for deprivation, as there were only small differences in NZDep between Pacific groups and it is a relatively crude and indirect measure of deprivation which is most useful when there are major differences between groups. Ethical approval—The PREDICT research project was approved by the Northern Region Ethics Committee Y in 2003 (AKY/03/12/314) and the national Multi Region Ethics Committee in 2007 (MEC/07/19/EXP). Results Between 2002 and June 2009, baseline PREDICT CVD risk assessments were conducted on 10,301 people aged 35-74 identifying with at least one Pacific ethnic group, after excluding those classified as Fijian (as discussed in the Methods). Of these, 48% identified as Samoan, 17% as Tongan, 13% as Cook Island Māori, 8% as Niuean and 14% as Other Pacific or Pacific NFD. Table 1 shows the baseline demographic characteristics of Pacific peoples in the PREDICT cohort by Level 2 ethnic group. In most Pacific groups, there were similar proportions of men and women receiving CVD risk assessments. The only exception to this was for the Tongan cohort (54% men). On average, Pacific women were approximately 3 years older than their male counterparts. The distribution of age groups at first CVD risk assessment was similar across Pacific groups, with approximately 25% aged 35-44, 35% aged 45-54 and 25% aged 55-64. All Pacific groups were over-represented in areas of high deprivation, with approximately 75% residing in the two most deprived NZDep01 quintiles (deciles 7-10). Table 2 presents the gender-specific age-adjusted risk ratios for three CVD risk factors (smoking, diabetes and a prior history of CVD) for Pacific groups, using Samoans as the reference group. There were no overall differences in the proportion of smokers among Pacific men (p=0.16). Cook Island women had the highest proportion of smokers among women (21%) and were almost 60% more likely than Samoan women to smoke. Niuean men had the highest burden of diabetes (almost 40%) among Pacific males. Pacific women in all groups had a higher prevalence of diabetes than their male counterparts, with over one-third of all Pacific women having a diagnosis of diabetes. Tongan women were 26% more likely, and Niuean women 17% more likely, than Samoan women to have diabetes. Overall differences between Pacific groups in the proportion with a prior history of CVD were small. Table 1. Baseline demographic characteristics of people in Pacific ethnic groups in the PREDICT cohort Variables Samoan Tongan Cook Island Māori Niuean Other Pacific/ Pacific NFD Total, n (%) 10301 4933 (48%) 1724 (17%) 1366 (13%) 880 (8%) 1398 (14%) Gender, n (%) Male Female 2586 (52%) 2347 (48%) 937 (54%) 787 (46%) 679 (50%) 687 (50%) 423 (48%) 457 (52%) 699 (50%) 699 (50%) Mean age (SD) Male Female 52.0 (9.8) 54.9 (9.2) 51.0 (10.0) 54.6 (9.4) 52.1 (10.1) 55.1 (9.5) 52.5 (10.0) 55.4 (9.8) 50.7 (9.7) 54.7 (9.0) Age group, n (%) 35-44 y 45-54 y 55-64 y 65-74 y 1209 (24%) 1724 (35%) 1367 (28%) 633 (13%) 482 (28%) 602 (35%) 418 (24%) 222 (13%) 316 (23%) 522 (38%) 301 (22%) 227 (17%) 203 (23%) 315 (36%) 208 (24%) 154 (17%) 354 (25%) 510 (37%) 379 (27%) 155 (11%) NZDep01 Deprivation quintiles, n (%) 1-2 3-4 5-6 7-8 9-10 111 (2%) 307 (6%) 625 (13%) 1469 (30%) 2416 (49%) 31 (2%) 99 (6%) 181 (10%) 416 (24%) 995 (58%) 41 (3%) 136 (10%) 185 (14%) 290 (21%) 712 (52%) 18 (2%) 61 (7%) 153 (17%) 247 (28%) 400 (46%) 64 (5%) 101 (7%) 192 (14%) 480 (34%) 557 (40%) Table 2. Age-adjusted estimates and risk ratios, with 95% confidence intervals, for smoking, diabetes and prior history of CVD for Pacific groups in PREDICT cohort by gender (reference group is Samoan) Pacific subgroup Male, n (%) with risk factor RR (95% CI) adjusted for age Female, n (%) with risk factor RR (95% CI) adjusted for age Smoking Samoan Tongan Cook Island Māori Niuean Pacific Other/NFD 684 (26%) 285 (29%) 183 (26%) 99 (23%) 176 (24%) Reference 1.13 (1.01-1.27) 1.02 (0.90-1.18) 0.90 (0.74-1.07) 0.93 (0.81-1.07) 312 (13%) 84 (10%) 144 (21%) 67 (15%) 92 (13%) Reference 0.79 (0.63-0.99) 1.59 (1.34-1.89) 1.12 (0.88-1.43) 0.97 (0.78-1.21) Diabetes Samoan Tongan Cook Island Māori Niuean Pacific Other/NFD 734 (28%) 271 (29%) 173 (25%) 161 (37%) 183 (26%) Reference 1.04 (0.93-1.16) 0.89 (0.78-1.03) 1.31 (1.15-1.48) 0.93 (0.81-1.07) 807 (32%) 346 (41%) 211 (29%) 187 (38%) 235 (32%) Reference 1.26 (1.15-1.39) 0.89 (0.79-1.01) 1.17 (1.04-1.32) 0.98 (0.88-1.10) History of CVD Samoan Tongan Cook Island Māori Niuean Pacific Other/NFD 264 (9%) 80 (8%) 81 (10%) 55 (11%) 84 (11%) Reference 0.89 (0.70-1.11) 1.13 (0.91-1.42) 1.23 (0.95-1.59) 1.29 (1.03-1.60) 192 (6%) 44 (4%) 58 (6%) 35 (6%) 56 (6%) Reference 0.70 (0.51-0.97) 1.01 (0.77-1.33) 0.90 (0.63-1.25) 1.01 (0.76-1.34) Table 3 shows the age-adjusted mean systolic and diastolic blood pressures (BPs), total cholesterol/HDL ratio and Framingham 5-year CVD risk scores of Pacific groups, by gender. Niuean men and women had the lowest mean systolic and diastolic BPs of all groups (mean systolic and diastolic BPs 2 to 3 mmHg lower than Samoans). Tongan men had the highest mean total cholesterol/HDL ratio (0.26 higher than Samoan men), and Niuean men the lowest (0.16 lower than Samoan men). Tongan women had the highest mean total cholesterol/HDL ratio (0.14 higher than Samoan women after adjusting for age and deprivation). Tongan men and women had the highest 5-year Framingham CVD risk scores and while these were statistically significantly higher than the Samoan reference categories, they only represented about a 10% relative difference in risk. Table 3. Age-adjusted mean values and mean differences for systolic and diastolic blood pressures, total cholesterol/HDL ratio and Framingham 5-year CVD risk score for Pacific groups in PREDICT cohort by gender (Reference group is Samoan) Pacific subgroup Male Age-adjusted mean (95% CI) Age-adjusted mean difference (95% CI) Female Age-adjusted mean (95% CI) Age-adjusted mean difference (95% CI) Systolic BP (mmHg) Samoan 131.2 (130.5 to 131.8) Reference 132.2 (131.4 to 132.9) Reference Tongan 131.7 (130.7 to 132.8) 0.6 (-0.7 to 1.8) 131.9 (130.6 to 133.2) -0.3 (-1.8 to 1.2) Cook Island 132.8 (131.5 to 134.0) 1.6 (0.2 to 3.0) 133.1 (131.7 to 134.5) 0.9 (-0.6 to 2.5) Niuean 128.7 (127.1 to 130.3) -2.5 (-4.2 to -0.8) 129.9 (128.2 to 131.6) -2.3 (-4.1 to -0.5) Pacific Other/NFD 132.7 (131.5 to 133.9) 1.6 (0.1 to 2.90) 133.9 (132.5 to 135.2) 1.7 (0.1 to 3.2) Diastolic BP (mmHg) Samoan 82.6 (82.2 to 83.1) Reference 82.0 (81.6 to 82.5) Reference Tongan 81.9 (81.1 to 82.6) -0.8 (-1.6 to 0.1) 80.7 (79.9 to 81.5) -1.3 (-2.2 to -0.5) Cook Island 83.5 (82.7 to 84.4) 0.9 (-0.1 to 1.8) 83.0 (82.2 to 83.8) 1.0 (0.1 to 1.9) Niuean 80.1 (79.0 to 81.2) -2.5 (-3.7 to -1.4) 79.1 (78.1 to 80.1) -2.9 (-4.0 to -1.8) Pacific Other/NFD 82.8 (82.0 to 83.7) 0.2 (-0.7 to 1.1) 81.8 (81.0 to 82.6) -0.2 (-1.2 to 0.7) Tot chol: HDL ratio Samoan 4.24 (4.19 to 4.29) Reference 3.78 (3.74 to 3.83) Reference Tongan 4.50 (4.42 to 4.59) 0.26 (0.16 to 0.36) 3.93 (3.85 to 4.00) 0.14 (0.05 to 0.23) Cook Island 4.32 (4.22 to 4.42) 0.08 (-0.04 to 0.18) 3.89 (3.81 to 3.97) 0.11 (0.01 to 0.20) Niuean 4.09 (3.96 to 4.21) -0.16 (-0.29 to -0.02) 3.75 (3.65 to 3.85) -0.03 (-0.14 to 0.08) Pacific Other/NFD 4.33 (4.23 to 4.43) 0.09 (-0.02 to 0.20) 3.83 (3.74 to 3.91) 0.05 (-0.05 to 0.14) Framingham 5yr CVD risk % Samoan 8.17 (7.99 to 8.34) Reference 5.20 (5.03 to 5.38) Reference Tongan 8.88 (8.57 to 9.18) 0.71 (0.36 to 1.06) 5.72 (5.42 to 6.02) 0.52 (0.17 to 0.86) Cook Island 8.51 (8.16 to 8.87) 0.35 (-0.05 to 0.75) 5.45 (5.13 to 5.77) 0.25 (-0.12 to 0.62) Niuean 7.86 (7.41 to 8.30) -0.30 (-0.79 to 0.17) 5.23 (4.83 to 5.62) 0.02 (-0.41 to 0.46) Pacific Other/NFD \