Risk factors, ethnic differences and mortality associated with lower-extremity gangrene and amputation in diabetes. The WHO multinational study of vascular disease in diabetes

Aims/hypothesis. We aimed to examine geographic differences, risk factors and mortality associated with amputation. Methods. Data from 10 of the original 14 centres of the WHO Multinational Study of Vascular Disease in Diabetes were used. This included 3443 men and women aged 35 to 55 years at baseline. Results. Incidences of amputation, adjusted for sex and duration in Type I (insulin-dependent) diabetes mellitus, were 31.0, 8.2, 3.5 and 1.0 per 1000 person years in the American Indian, Cuban, European and East Asian centres respectively. In Type II (non-insulin-dependent) diabetes mellitus, incidences of amputation were 9.7, 2.0, 2.5 and 0.7 per 1000 person years in the American Indian, Cuban, European and East Asian centres respectively. Key risk factors for amputation included glucose, triglyceride, and retinopathy, and were similar for American Indians and Europeans. The age, duration and sex adjusted relative risk for amputation in American Indians compared with Europeans was 11.48 (95% CI 3.56, 36.98) in Type I diabetes and 3.86 (95% CI 2.36, 6.32) in Type II diabetes. Adjusting for heart disease, retinopathy, proteinuria, glucose, blood pressure and triglyceride attenuated these relative risks to 10.83 (95% CI 3.20, 36.65) and 3.15 (1.91, 5.20) in Type I and Type II diabetes respectively. Amputation doubled mortality rates in all groups. Conclusion/interpretation. Vascular complications and their risk factors are themselves risk factors for amputation in both Type I and Type II diabetes and are common to several geographical regions worldwide. However, reasons for differences between geographical regions and the degree to which different health care systems could be responsible is not clear.