Ethnicity and risk of diabetes-related lower extremity amputation: a population-based, case-control study of African Caribbeans and Europeans in the United kingdom.

Abstract

In the United States, people of black African descent with diabetes have 2 to 3 times the amputation risk of whites. This may be due to differences in care or pathophysiological characteristics. We therefore determined diabetes-related amputation rates in African Caribbeans vs Europeans in the United Kingdom, where care delivery is more equitable. We conducted an incidence and case-control study, based in London, England. All diabetes-related amputations performed between 1992 and 1997 were identified. Controls, those with diabetes but no amputation, were sampled from family practitioners. Risk factor data were abstracted from medical records. Incident diabetes-related amputation occurred in 67 Europeans and 19 African Caribbeans. Amputation rates, age standardized to the diabetic population, were 147 per 100 000 and 219 per 100 000 in African Caribbeans and Europeans, respectively (relative risk, 0.67; 95% confidence interval [CI], 0.32-1.40; P =.2). Case-control analyses were performed on 178 cases and 350 controls. The ethnic difference in amputation risk differed significantly by sex (P =.009 for interaction). The unadjusted odds ratio comparing African Caribbeans with Europeans in men was 0.31 (95% CI, 0.17-0.57; P<.001), and in women was 0.97 (95% CI, 0.49-1.85; P =.9). Adjustment for smoking attenuated the odds ratio in men to 0.45 (95% CI, 0.23-0.89, P =.02); adding neuropathy, peripheral vascular disease, and age attenuated the odds ratio further to 0.97 (95% CI, 0.34-2.73; P =.9). In contrast to the United States, we find no ethnic difference in diabetes-related amputation in women in the United Kingdom, but in men, amputation risk in African Caribbeans is one third that of Europeans. This was wholly accounted for by low smoking, neuropathy, and peripheral vascular disease rates.