Does ethnic origin have an independent impact on hypertension and diabetic complications?

The morbidity and mortality from cardiovascular complications in diabetes reputedly differ with ethnicity. We have evaluated the prevalence of hypertension and vascular complications amongst Afro-Caribbean (AC), Caucasian (C) and Indo-Asian (IA) ethnic subgroups of a district's diabetes population to estimate the impact of ethnic origin as an independent risk variable.

Of the 6485 registered adult individuals, 6047 had ethnic data available and belonged to one of the three ethnic groups described (AC 9%, C 70% and IA 21%). Statistical analyses were performed using spss version 11.5.

Results are presented as mean +/- s.d. or percentage. IAs were younger (AC 63 +/- 13, C 61 +/- 15 and IA 57 +/- 13 years), were less obese (body mass index 30 +/- 8, 29 +/- 9, 28 +/- 6 kg/cm2) and had lower systolic blood pressure (155 +/- 25, 149 +/- 24, 147 +/- 24 mmHg) and lower prevalence of hypertension (82%, 74% and 68%) compared with C, who had lower values than AC (all p < 0.01). Relative to C group, the AC group had higher prevalence of hypertension and microvascular complications but lower macrovascular disease burden, while the IA group had lower hypertension and macrovascular complications but with comparable microvascular disease burden [microvascular (51%, 44% and 46%; p < 0.01) and macrovascular (33%, 40% and 32%; p < 0.001)]. On logistic regression, this effect of ethnic origin on diabetic complications was found to be significant and independent of other risk variables.

Hypertension and diabetic complication rates were different amongst ethnic subgroups. On logistic regression, it was found that the difference in distribution of age and diabetes duration largely accounted for this difference, although ethnic origin remained an independent risk factor.