An association between ethnicity and cardiovascular outcomes for people with Type 2 diabetes in New Zealand

Aims To investigate the association between ethnicity and risk of first cardiovascular (CV) event for people with Type 2 diabetes in New Zealand. Methods A prospective cohort study using routinely collected data from a national primary health care diabetes annual review programme linked to national hospital admission and mortality data. Ethnicity was recorded as European, Maori, Pacific, Indo‐Asian, East‐Asian or Other. A Cox proportional hazards model was used to investigate factors associated with first CV event. Data was collected from 48 444 patients with Type 2 diabetes, with first data collected between 1 January 2000 and 20 December 2005, no previous cardiovascular event at entry and with complete measurements. Risk factors included ethnicity, gender, socio‐economic status, body mass index, smoking, age at diagnosis, duration of diabetes, systolic blood pressure, serum lipids, glycated haemoglobin and urine albumin : creatinine ratio. The main outcome measures were time to first fatal or non‐fatal CV event. Results Median follow‐up was 2.4 years. Using combined European and Other ethnicities as a reference, hazard ratios for first CV event were 1.30 for Maori (95% confidence interval 1.19–1.41), 1.04 for Pacific (0.95–1.13), 1.06 for Indo‐Asian (0.91–1.24) and 0.73 for East‐Asian (0.62–0.85) after controlling for all other risk factors. Conclusions Ethnicity was independently associated with time to first CV event in people with Type 2 diabetes. Maori were at 30% higher risk of first CV event and East‐Asian 27% lower risk compared with European/Other, with no significant difference in risk for Pacific and Indo‐Asian peoples.