The contribution of non-insulin-dependent diabetes to lower-extremity amputation in the community.

Background: Despite the significant public health burden of lower-extremity amputations in diabetes mellitus, few data are available on the epidemiology of lower-extremity amputations in diabetes mellitus in the community setting.

Methods: A retrospective incidence cohort study based in Rochester, Minn, was conducted.

Results: Among the 2015 diabetic individuals free of lower-extremity amputation at the diagnosis of diabetes mellitus, 57 individuals underwent 79 lower-extremity amputations (incidence, 375 per 100,000 person-years; 95% confidence interval, 297 to 467). Among the 1826 patients with non-insulin-dependent diabetes mellitus, 52 underwent 73 lower-extremity amputations, and the subsequent incidence of lower-extremity amputation among these residents was 388 per 100,000 person-years (95% confidence interval, 304 to 487). Of the 137 insulin-dependent diabetic patients, four subsequently underwent five lower-extremity amputations (incidence, 283 per 100,000 person-years; 95% confidence interval, 92 to 659). Twenty-five years after the diagnosis of diabetes mellitus, the cumulative risk of one lower-extremity amputation was 11.2% in insulin-dependent diabetes mellitus and 11.0% in non-insulin-dependent diabetes mellitus. When compared with lower-extremity amputation rates for Rochester residents without diabetes, patients with non-insulin-dependent diabetes mellitus were nearly 400 times more likely to undergo an initial transphalangeal amputation (rate ratio, 378.8) and had almost a 12-fold increased risk of a below-knee amputation (rate ratio, 11.8). In this community, more than 60% of lower-extremity amputations were attributable to non-insulin-dependent diabetes mellitus.

Conclusions: These population-based data document the magnitude of the elevated risk of lower-extremity amputation among diabetic individuals. Efforts should be made to identify more precisely risk factors for amputation in diabetes and to intervene in the processes leading to amputation.