Cardiovascular disease risk prediction equations in 400 000 primary care patients in New Zealand: a derivation and validation study.

BACKGROUND: Most cardiovascular disease risk prediction equations in use today were derived from cohorts established last century and with participants at higher risk but less socioeconomically and ethnically diverse than patients they are now applied to. We recruited a nationally representative cohort in New Zealand to develop equations relevant to patients in contemporary primary care and compared the performance of these new equations to equations that are recommended in the USA. METHODS: The PREDICT study automatically recruits participants in routine primary care when general practitioners in New Zealand use PREDICT software to assess their patients' risk profiles for cardiovascular disease, which are prospectively linked to national ICD-coded hospitalisation and mortality databases. The study population included male and female patients in primary care who had no prior cardiovascular disease, renal disease, or congestive heart failure. New equations predicting total cardiovascular disease risk were developed using Cox regression models, which included clinical predictors plus an area-based deprivation index and self-identified ethnicity. Calibration and discrimination performance of the equations were assessed and compared with 2013 American College of Cardiology/American Heart Association Pooled Cohort Equations (PCEs). The additional predictors included in new PREDICT equations were also appended to the PCEs to determine whether they were independent predictors in the equations from the USA. FINDINGS: Outcome events were derived for 401 752 people aged 30-74 years at the time of their first PREDICT risk assessment between Aug 27, 2002, and Oct 12, 2015, representing about 90% of the eligible population. The mean follow-up was 4·2 years, and a third of participants were followed for 5 years or more. 15 386 (4%) people had cardiovascular disease events (1507 [10%] were fatal, and 8549 [56%] met the PCEs definition of hard atherosclerotic cardiovascular disease) during 1 685 521 person-years follow-up. The median 5-year risk of total cardiovascular disease events predicted by the new equations was 2·3% in women and 3·2% in men. Multivariable adjusted risk increased by about 10% per quintile of socioeconomic deprivation. Maori, Pacific, and Indian patients were at 13-48% higher risk of cardiovascular disease than Europeans, and Chinese or other Asians were at 25-33% lower risk of cardiovascular disease than Europeans. The PCEs overestimated of hard atherosclerotic cardiovascular disease by about 40% in men and by 60% in women, and the additional predictors in the new equations were also independent predictors in the PCEs. The new equations were significantly better than PCEs on all performance metrics. INTERPRETATION: We constructed a large prospective cohort study representing typical patients in primary care in New Zealand who were recommended for cardiovascular disease risk assessment. Most patients are now at low risk of cardiovascular disease, which explains why the PCEs based mainly on old cohorts substantially overestimate risk. Although the PCEs and many other equations will need to be recalibrated to mitigate overtreatment of the healthy majority, they also need new predictors that include measures of socioeconomic deprivation and multiple ethnicities to identify vulnerable high-risk subpopulations that might otherwise be undertreated. FUNDING: Health Research Council of New Zealand, Heart Foundation of New Zealand, and Healthier Lives National Science Challenge.

Access and society as determinants of ischaemic heart disease in indigenous populations.

BACKGROUND: Ischaemic Heart Disease (IHD) is a leading cause of death in New Zealand and the burden falls disproportionately on Maori, the indigenous population of Aotearoa New Zealand. METHODS: Data for Maori:non-Maori disparities in risk factors, hospitalisation, procedure receipt and mortality for IHD are analysed. Age-adjusted rates of IHD mortality (2000-2004) and publicly funded hospitalisations and procedures (2003-2005) for Maori and non-Maori are reported and compared. RESULTS: Significant inequalities between Maori and non-Maori in IHD risk factors, hospitalisations, mortality and the receipt of related procedures exist. IHD hospitalisation rates for Maori are 1.4 times that of non-Maori, however mortality rates are more than twice that of non-Maori. In recent years Maori revascularisation rates have increased (as have non-Maori rates) but are still considerably less than might be expected given the much higher mortality rates. CONCLUSION: Despite high need, Maori receive relatively low access to appropriate care for IHD. The role of society, policy, and the clinician are three key factors to be considered in reducing inequalities for IHD between Maori and non-Maori.

Improving cardiovascular care for indigenous populations.

The challenges and opportunities for provision of, and access to, reliable chronic cardiovascular health care for Indigenous people were addressed by expert speakers from New Zealand and Australia. It is well recognised that cardiovascular disease is a life-long concern, requiring reliable follow-up, early transition of clinical research into practice and ongoing support of patients. The clinical outcomes and long-term prognosis of individuals with cardiovascular disease are critically dependent upon the quality and availability of follow-up and chronic care facilities. This paper summarises the principal issues identified by the expert speakers for the provision of chronic cardiovascular health care to Indigenous peoples in Australia and New Zealand; identifies common challenges and describes important initiatives which the Cardiac Society of Australia and New Zealand (CSANZ), in partnership with health care professionals, communities and governments, can undertake in order to achieve the goals of uniform and equitable health care for chronic cardiovascular disease in all the Indigenous peoples, relevant to the needs of these peoples, in New Zealand and Australia. The issues addressed by the meeting include: 1) Determination of appropriate models for effective delivery of cardiovascular health care. (2) Who should deliver cardiovascular health care and what are the workforce requirements. (3) What support systems and infrastructure are required. (4) How can primary care and secondary specialist services be effectively integrated.

Rheumatic heart disease in indigenous populations.

Rates of acute rheumatic fever and chronic rheumatic heart disease in Aboriginal people, Torres Strait Islanders and Maori continue to be unacceptably high. The impact of rheumatic heart disease is inequitable on these populations as compared with other Australians and New Zealanders. The associated cardiac morbidity, including the development of rheumatic valve disease, and cardiomyopathy, with possible sequelae of heart failure, development of atrial fibrillation, systemic embolism, transient ischaemic attacks, strokes, endocarditis, the need for interventions including cardiac surgery, and impaired quality of life, and shortened life expectancy, has major implications for the individual. The adverse health and social effects may significantly limit education and employment opportunities and increase dependency on welfare. Additionally there may be major adverse impacts on family and community life. The costs in financial terms and missed opportunities, including wasted young lives, are substantial. Prevention of acute rheumatic fever is dependent on the timely diagnosis and treatment of sore throats and skin infections in high-risk groups. Both Australia and New Zealand have registries for acute rheumatic fever but paradoxically neither includes all cases of chronic rheumatic heart disease many of whom would benefit from close surveillance and follow-up. In New Zealand and some Australian States there are programs to give secondary prophylaxis with penicillin, but these are not universal. Surgical outcomes for patients with rheumatic valvular disease are better for valve repair than for valve replacement. Special attention to the selection of the appropriate valve surgery and valve choice is required in pregnant women. It may be necessary to have designated surgical units managing Indigenous patients to ensure high rates of surgical repair rather than valve replacement. Surgical guidelines may be helpful. Long-term follow-up of the outcomes of surgery in Indigenous patients with rheumatic heart disease is required. Underpinning these strategies is the need to improve poverty, housing, education and employment. Cultural empathy with mutual trust and respect is essential. Involvement of Indigenous people in decision making, design, and implementation of primary and secondary prevention programs, is mandatory to reduce the unacceptably high rates of rheumatic heart disease.

Ethnic differences in cardiovascular risk profiles among 475,241 adults in primary care in Aotearoa, New Zealand.

AIM: In Aotearoa, New Zealand, cardiovascular disease (CVD) burden is greatest among Indigenous Maori, Pacific and Indian people. The aim of this study was to describe CVD risk profiles by ethnicity. METHODS: We conducted a cross-sectional analysis of a cohort of people aged 35-74 years who had a CVD risk assessment in primary care between 2004 and 2016. Primary care data were supplemented with linked data from regional/national databases. Comparisons between ethnic groups were made using age-adjusted summaries of continuous or categorical data. RESULTS: 475,241 people (43% women) were included. Fourteen percent were Maori, 13% Pacific, 8% Indian, 10% Other Asian and 55% European. Maori and Pacific people had a much higher prevalence of smoking, obesity, heart failure, atrial fibrillation and prior CVD compared with other ethnic groups. Pacific and Indian peoples, and to a lesser extent Maori and Other Asian people, had markedly elevated diabetes prevalence compared with Europeans. Indian men had the highest prevalence of prior coronary heart disease. CONCLUSIONS: Maori and Pacific people experience the most significant inequities in exposure to CVD risk factors compared with other ethnic groups. Indians have a high prevalence of diabetes and coronary heart disease. Strong political commitment and cross-sectoral action to implement effective interventions are urgently needed.

The distribution and frequency of blood lipid testing by sociodemographic status among adults in Auckland, New Zealand.

INTRODUCTION: National cardiovascular disease (CVD) guidelines recommend that adults have cholesterol levels monitored regularly. However, little is known about the extent and equity of cholesterol testing in New Zealand. AIM: To investigate the distribution and frequency of blood lipid testing by sociodemographic status in Auckland, New Zealand. METHODS: We anonymously linked five national health datasets (primary care enrolment, laboratory tests, pharmaceuticals, hospitalisations and mortality) to identify adults aged ≥25 years without CVD or diabetes who had their lipids tested in 2006-2010, by age, gender, ethnicity and area of residence and deprivation. Multivariate logistic regression was used to estimate the likelihood of testing associated with these factors. RESULTS: Of the 627 907 eligible adults, 66.3% had at least one test between 2006 and 2010. Annual testing increased from 24.7% in 2006 to 35.1% in 2010. Testing increased with age similarly for men and women. Indian people were 87% more likely than New Zealand European and Others (NZEO) to be tested, Pacific people 8% more likely, but rates for Maori were similar to NZEO. There was marked variation within the region, with residents of the most deprived areas less likely to be tested than residents in least deprived areas. DISCUSSION: Understanding differences within and between population groups supports the development of targeted strategies for better service utilisation. While lipid testing has increased, sociodemographic variations persist by place of residence, and deprivation. Of the high CVD risk populations, lipid testing for Maori and Pacific is not being conducted according to need.

Twenty-eight day and one-year case fatality after hospitalisation with an acute coronary syndrome: a nationwide data linkage study.

OBJECTIVES: To determine 28-day and one-year case fatality in patients hospitalised with acute coronary syndromes (ACS) and identify factors associated with mortality. METHODS: All New Zealand residents admitted with ACS between 2007 and 2009 were followed for one year using individual patient linkage of national hospitalisation and mortality datasets. Deaths from any cause were used to calculate 28-day and one-year case fatality. Cox-proportional hazards models were constructed to identify factors associated with mortality after an ACS hospitalisation. RESULTS: The cohort included 42,920 ACS patients. Case fatality increased steeply with age. Maori and Pacific peoples had 1.5 times the risk of 28-day, and twice the risk of one-year, mortality as Europeans/Others. Low (compared to high) socioeconomic status was associated with significantly higher mortality at 28 days but not one year. Patients with unstable angina had half the risk of short-term mortality as NSTEMI patients, whereas STEMI patients had double the NSTEMI risk. CONCLUSIONS AND IMPLICATIONS: The major determinant of increasing case fatality was increasing age. There were also substantial differences in case fatality by ethnicity, deprivation and diagnostic category. Further research is needed to explore the possible mechanisms by which ethnic and deprivation disparities occur and effective strategies to address them.

Ethnicity and revascularisation following acute coronary syndromes: a 5-year cohort study (ANZACS-QI-3).

BACKGROUND: Prior studies have reported higher rates of coronary revascularisation in European compared with Maori and Pacific patients. Our aim was to define the current variation by ethnicity in investigation, revascularisation and pharmacotherapy after admission with an acute coronary syndrome (ACS). METHODS: Data from consecutive New Zealand residents <80 years of age admitted to the Middlemore Hospital coronary care unit with ACS (2007 to 2012) were collected prospectively. RESULTS: Of 2666 ACS patients <80y, 51.5% were European/Other, 14.2% Maori, 16.0% Pacific, 14.8% Indian, and 3.5% Asian. Cardiac risk factors and comorbidity varied markedly by ethnicity. The overall coronary angiography rate was high (89%). After adjustment for clinical factors which influence the decision to perform angiography, European/Other patients were about 5% more likely than Maori and Pacific patients to have angiography. Overall revascularisation was highest in Asian, Indian and European/Other (76.1%, 69.1% and 68.6%), and lower in Maori and Pacific patients (58.2% and 52.9%). Non-obstructive coronary disease was more common in Maori and Pacific (20.6 and 18.6%, respectively), than in European/Other, Indian and Asian patients (13.3%, 8.7% and 6.1%). After adjustment, Maori, Indian and Asian patients were as likely to receive revascularisation as European/Others, but revascularisation in Pacific patients was 13% lower. Discharge prescribing of triple preventive therapy was uniformly high across ethnic groups (overall 91%). CONCLUSIONS: There is a small unexplained variation in angiography rates across ethnic groups. Much of the observed variation in revascularisation may be due to differences in the coronary artery disease phenotype.

Effect of age, gender, ethnicity, socioeconomic status and region on dispensing of CVD secondary prevention medication in New Zealand: the Atlas of Health Care Variation CVD cohort (VIEW-1).

BACKGROUND: Triple therapy with anti-platelet/anti-coagulant, blood pressure (BP)-lowering, and statin medications improves outcomes in atherosclerotic cardiovascular disease (CVD). However, in practice there is often a substantial evidence-practice gap, with sub-optimal initiation and longer-term adherence. Our aim was to enumerate a contemporary national cohort of people with significant CVD and report the variation in CVD secondary prevention dispensing by demographic variables. METHODS: Using anonymised linkage of national data sets, we identified 86,256 individuals, alive and residing in New Zealand at the end of 2010, aged 30-79 years who were hospitalised for an atherosclerotic CVD event or procedure in the previous10 years. This cohort was linked to the national pharmaceutical dispensing dataset to assess dispensing of CVD prevention medications during the 2011 calendar year. Adequate dispensing was defined as being dispensed a drug in at least 3 of the 4 quarters of the year. Multivariate regression was used to identify independent predictors of adequate dispensing. RESULTS: 59% were maintained on triple therapy, 77% on BP-lowering medication, 75% on anti-platelet/anti-coagulants and 70% on statins. From multivariate analysis, patients less than 50 years were about 20% less likely than older patients and women were 10% less likely than men to be maintained on triple therapy. Indian patients were about 10% more likely to be maintained on triple therapy than NZ European/Others. Those living in the Southern Cardiac Network region of New Zealand had slightly higher rates of triple therapy than National Cardiac Regions further north. CONCLUSIONS: The significant under-utilisation of safe and inexpensive secondary prevention medication, particularly in younger people and women, provides an opportunity to improve CVD outcomes in this easily identifiable high-risk population.

Maintenance of statin use over 3 years following acute coronary syndromes: a national data linkage study (ANZACS-QI-2).

OBJECTIVE: To describe patterns of statin use and predictors of poor maintenance over a 3-year period following an acute coronary syndrome (ACS). METHODS: National hospitalisation, mortality and pharmaceutical dispensing data were linked for all subjects aged 35-84 years discharged from a public hospital with an ACS in New Zealand in 2007. A Medication Possession Ratio (MPR; percentage of follow-up days patients were dispensed statins) was calculated for each patient. Adequate maintenance was defined by a MPR ≥80%. RESULTS: In 2007, 11 348 patients aged 35-84 years were discharged from hospital with ACS. Within 90 days of discharge, 83% had received a statin. Over the follow-up period, 66% were adequately maintained on a statin (MPR ≥80%): 69% in the first year, 67% in the second year and 66% in the third year. Patients taking statins prior to admission and those who underwent a coronary procedure were 20-50% more likely to have a MPR ≥80% over 3 years than others. In contrast, people aged 35-45 years and those of Maori or Pacific ethnicity were 13-25% less likely to have a MPR ≥80% than those aged 55-64 years and Europeans. CONCLUSIONS: One-third of patients were not adequately maintained on statins over the 3-year period following ACS, but 82% of those on a statin prior to admission had an MPR ≥80% over 3 years of follow-up. These findings define achievable treatment levels and identify groups who may benefit from efforts to improve statin use.

Initiation and maintenance of cardiovascular medications following cardiovascular risk assessment in a large primary care cohort: PREDICT CVD-16.

AIM: To examine whether use of a standardized cardiovascular disease (CVD) risk assessment recommended by national guidelines is associated with appropriate initiation and maintenance of medication in a large primary care cohort. METHODS AND DESIGN: A total of 90,631 people aged 30-80 years were followed for up to 3 years after a formal CVD risk assessment was undertaken between January 2006 and October 2009, during routine primary care visits in New Zealand. Patients either had prior CVD or had their CVD risk estimated using a modified Framingham prediction equation for fatal or non-fatal CVD events. The individual risk profiles were anonymously linked to national dispensing data for blood-pressure-lowering and lipid-lowering medications in the 6-month period before and in consecutive 6-month blocks after the baseline CVD risk assessment. RESULTS: At baseline, a combination of blood-pressure-lowering and lipid-lowering therapy was already being used by about two-thirds of patients with prior CVD, one-quarter with a 5-year CVD risk greater than 10% (approximately 20% 10-year risk), and one-tenth with CVD risk below this level. Among these previously treated patients, dispensing rates for blood-pressure-lowering, lipid-lowering, or both medications together declined by only 4⊟16% up to 3 years after baseline assessment, irrespective of risk category. Among patients untreated at baseline, combination therapy was initiated within 6 months for 21% with prior CVD, 16% with 5-year CVD risk greater than 15% (approximately 30% 10-year risk and the national drug-treatment threshold), 10% with 5-year CVD risk between 10 and 14% (approximately 20⊟29% 10-year risk), and 3% in the lowest risk category. Across the study population, patients with prior CVD had the highest dispensing rates for each category of medication, and incrementally higher dispensing rates were noted as CVD risk group increased. CONCLUSIONS: In this primary care cohort, most patients already using CVD medications at the time of the baseline CVD risk assessment maintained treatment over a maximum of 3 years follow up, irrespective of their estimated baseline risk. Among patients untreated at baseline, subsequent dispensing rates were strongly related to estimated CVD risk group. Around 15⊟20% of untreated patients meeting national drug-treatment criteria commenced combination pharmacotherapy within 6 months of CVD risk assessment.

Markedly different clustering of CVD risk factors in New Zealand Indian and European people but similar risk scores (PREDICT-14).

OBJECTIVE: To compare the cardiovascular disease (CVD) risk profiles of Indian and European patients from routine primary care assessments in the northern region of New Zealand. METHOD: Anonymous CVD risk profiles were extracted from PREDICT (a web-based decision support program) for Indian and European patients aged 35-74 years. Linear regression models were used to obtain mean differences adjusted for age, gender and deprivation. RESULTS: At recruitment, Indian participants (n=8,830) were younger than Europeans (n=47,091), in keeping with national guidelines that recommend earlier CVD risk assessment for Indians. Compared with Europeans, a greater proportion of Indian participants lived in areas of higher deprivation and had a two to four-fold greater burden of diabetes in all age groups. Indian participants had a significantly lower proportion of smokers and a lower mean systolic blood pressure. The respective cardiovascular risk factor profiles lead to similar age-adjusted Framingham five-year CVD risk scores. CONCLUSIONS AND IMPLICATIONS: National data sources indicate that there are higher rates of hospitalisations and deaths from CVD in Indians compared with Europeans. Our study found similar predicted CVD risk in these two populations despite markedly different clustering of risk factors, suggesting that the Framingham risk equation may underestimate risk in Indians. There is a need for better ethnicity coding to identify all South Asian ethnicities.

New Zealand Diabetes Cohort Study cardiovascular risk score for people with Type 2 diabetes: validation in the PREDICT cohort.

INTRODUCTION: New Zealand (NZ) guidelines recommend treating people for cardiovascular disease (CVD) risk on the basis of five-year absolute risk using a NZ adaptation of the Framingham risk equation. A diabetes-specific Diabetes Cohort Study (DCS) CVD predictive risk model has been developed and validated using NZ Get Checked data. AIM: To revalidate the DCS model with an independent cohort of people routinely assessed using PREDICT, a web-based CVD risk assessment and management programme. METHODS: People with Type 2 diabetes without pre-existing CVD were identified amongst people who had a PREDICT risk assessment between 2002 and 2005. From this group we identified those with sufficient data to allow estimation of CVD risk with the DCS models. We compared the DCS models with the NZ Framingham risk equation in terms of discrimination, calibration, and reclassification implications. RESULTS: Of 3044 people in our study cohort, 1829 people had complete data and therefore had CVD risks calculated. Of this group, 12.8% (235) had a cardiovascular event during the five-year follow-up. The DCS models had better discrimination than the currently used equation, with C-statistics being 0.68 for the two DCS models and 0.65 for the NZ Framingham model. DISCUSSION: The DCS models were superior to the NZ Framingham equation at discriminating people with diabetes who will have a cardiovascular event. The adoption of a DCS model would lead to a small increase in the number of people with diabetes who are treated with medication, but potentially more CVD events would be avoided.

Sociodemographic differences in prevalence of diagnosed coronary heart disease in New Zealand estimated from linked national health records.

AIM: To estimate sociodemographic differences in the prevalence of coronary heart disease (CHD) in New Zealand from linked health records. METHODS: We combined records of hospital treatment for CHD, dispensing of selected anti-anginal drugs and mortality to estimate the national point prevalence of coronary heart disease in New Zealand in December 2008. Stratified estimates are presented by gender; age; Maori, Pacific, Indian and 'Other' (mainly New Zealand European) ethnic groups; and socioeconomic status. RESULTS: Among a "health contact" population of adults (greater than and equal to 15 years), about one in twenty (6.5% of men and 4.1% of women) had indicators of a past diagnosis or treatment for CHD or both. Substantial differences in prevalence occurred by gender, ethnic group and socioeconomic status. For example, among New Zealanders aged 35 to 74 years, Indian men had the highest age-adjusted prevalence (7.78%; 95%CI 7.43 to 8.15), almost double the prevalence of 'Other' males. Among women, Maori had the highest adjusted prevalence (4.03%; 95% CI 3.89 to 4.17), just over twice that of 'Others.' CONCLUSION: Major sociodemographic disparities in the national burden of CHD persist. Our results are similar to previous studies of ethnic disparities in CHD incidence, but also confirm concerns about the emerging CHD burden among South Asians. Indian males have the highest CHD prevalence of any gender-specific ethnic group. Of equal concern, Maori women have a similar prevalence to European males.

Under-utilisation of preventive medication in patients with cardiovascular disease is greatest in younger age groups (PREDICT-CVD 15).

INTRODUCTION: Blood pressure-lowering (BPL) and lipid-lowering (LL) medications together reduce estimated absolute five-year cardiovascular disease (CVD) risk by >40%. International studies indicate that the proportion of people with CVD receiving pharmacotherapy increases with advancing age. AIM: To compare BPL and LL medications, by sociodemographic characteristics, for patients with known CVD in primary care settings. METHODS: The study population included patients aged 35-74 with known CVD assessed in primary care from July 2006 to October 2009 using a web-based computerised decision support system (PREDICT) for risk assessment and management. Clinical data linked anonymously to national sociodemographic and pharmaceutical dispensing databases. Differences in dispensing BPL and LL medications in six months before first PREDICT assessment was analysed according to age, sex, ethnicity and deprivation. RESULTS: Of 7622 people with CVD, 1625 <55 years old, 2862 were women and 4609 lived in deprived areas (NZDep quintiles 4/5). The study population included 4249 European, 1556 Maori, 1151 Pacific and 329 Indian peoples. BPL medications were dispensed to 81%, LL medications to 73%, both BPL and LL medications to 67%, and 87% received either class of medication. Compared with people aged 65-75, people aged 35-44 were 30-40% less likely and those aged 45-54 were 10-15% less likely to be dispensed BPL, LL medications or both. There were minimal differences in likelihood of dispensing according to sex, ethnicity or deprivation. DISCUSSION: BPL and LL medications are under-utilised in patients with known CVD in New Zealand. Only two-thirds of patients in this cohort are on both. Younger patients are considerably less likely to be on recommended medications.

A population-based approach to the estimation of diabetes prevalence and health resource utilisation.

AIM: This study estimated diabetes prevalence and utilisation of healthcare services in Counties Manukau using routinely collected administrative data and compared estimates with findings for three other district health boards (DHBs) in close geographic proximity. METHOD: Records of subsidy claims for pharmaceuticals and laboratory investigations were linked to records in a national hospital admissions database to 'reconstruct' populations of four DHBs--Counties Manukau, Northland, Waitemata and Auckland. Individuals were included in reconstructed populations if they had health events recorded between January 2006 and December 2007. Diabetes cases were identified using an algorithm based on claims for monitoring tests and pharmaceuticals, as well as clinical codes for diabetes in hospital admissions. RESULTS: Reconstructed populations were only 6% lower than census population counts indicating that the vast majority of the population use health services in a two year period. The age- and sex-standardised prevalence of diabetes was 7.1% in Counties Manukau and 5.2% in the other three DHBs combined. Prevalence of diabetes was highest amongst Maori (10.6% in women and 12.2% in men) and Pacific peoples (15.0% for women and 13.5% for men). Maori diabetes cases had the highest hospital discharge rate of any ethnic group. Community pharmaceutical prescribing patterns and laboratory test frequency were similar between diabetes cases by ethnicity and deprivation. CONCLUSION: Estimates of diabetes prevalence using linkage of routinely collected administrative data were consistent with epidemiological surveys, suggesting that linkage of pharmaceutical and laboratory subsidy databases with hospital admissions data can be used as an alternative to traditional surveys for estimating the prevalence of some long-term conditions. This study demonstrated substantial differences in the prevalence of diabetes and in hospitalisation rates by ethnicity, but measures of community diabetes care were similar by ethnicity and deprivation.

Performance of Framingham cardiovascular risk scores by ethnic groups in New Zealand: PREDICT CVD-10.

AIM: To compare the calibration performance of the original Framingham Heart Study risk prediction score for cardiovascular disease and an adjusted version of the Framingham score used in current New Zealand cardiovascular risk management guidelines for high and low risk ethnic groups. METHODS: Since 2002 cardiovascular risk assessments have been undertaken as part of routine clinical care in many New Zealand primary care practices using PREDICT, a web-based decision support programme for assessing and managing cardiovascular risk. Individual risk profiles from PREDICT were electronically and anonymously linked to national hospital admissions and death registrations in January 2008. Calibration performance was investigated by comparing the observed 5-year cardiovascular event rates (deaths and hospitalisations) with predicted rates from the Framingham and New Zealand adjusted Framingham scores. Calibration was examined in a combined 'high risk' ethnic group (Maori, Pacific and Indian) and a European 'low risk' ethnic group. There was insufficient person-time follow-up for separate analyses in each ethnic group. The analyses were restricted to PREDICT participants aged 30-74 years with no history of previous cardiovascular disease. RESULTS: Of the 59,344 participants followed for a mean of 2.11 years (125,064 person years of follow-up), 1,374 first cardiovascular events occurred. Among the 35,240 European participants, 759 cardiovascular events occurred during follow-up, giving a mean observed 5-year cumulative incidence of 4.5%. There were 582 events among the 21,026 Maori, Pacific and Indian participants, corresponding to a mean 5-year cumulative incidence rate of 7.4%. For Europeans, the original Framingham score overestimated 5-year risk by 0.7-3.2% at risk levels below 15% and by about 5% at higher risk levels. In contrast, for Maori, Pacific, and Indian patients combined, the Framingham score underestimated 5-year cardiovascular risk by 1.1-2.2% in participants who scored below 15% 5-year predicted risk (the recommended threshold for drug treatment in New Zealand), and overestimated by 2.4-4.1% the risk in those who scored above the 15% threshold. For both high risk and low risk ethnic groups, the New Zealand adjusted score systematically overestimated the observed 5-year event rate ranging from 0.6-5.3% at predicted risk levels below 15% to 5.4-9.3% at higher risk levels. CONCLUSION: The original Framingham Heart Study risk prediction score overestimates risk for the New Zealand European population but underestimates risk for the combined high risk ethnic populations. However the adjusted Framingham score used in New Zealand clinical guidelines overcompensates for this underestimate, resulting in a score that overestimates risk among the European, Maori, Pacific and Indian ethnic populations at all predicted risk levels. When sufficient person years of follow-up are available in the PREDICT cohort, new cardiovascular risk prediction scores should be developed for each of the ethnic groups to allow for more accurate risk prediction and targeting of treatment.