THE CONTRIBUTION OF NON-INSULIN-DEPENDENT DIABETES TO LOWER-EXTREMITYAMPUTATION IN THE COMMUNITY

Background: Despite the significant public health burden of lower-extr emity amputations in diabetes mellitus, few data are available on the epidemiology of lower-extremity amputations in diabetes mellitus in th e community setting. Methods: A retrospective incidence cohort study b ased in Rochester, Minn, was conducted. Results: Among the 2015 diabet ic individuals free of lower-extremity amputation at the diagnosis of diabetes mellitus, 57 individuals underwent 79 lower-extremity amputat ions (incidence, 375 per 100 000 person-years; 95% confidence interval , 297 to 467). Among the 1826 patients with non-insulin-dependent diab etes mellitus, 52 underwent 73 lower-extremity amputations, and the su bsequent 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 u ndenwent five lower-extremity amputations (incidence, 283 per 100 000 person-years; 95% confidence interval, 92 to 659). Twenty-five years a fter the diagnosis of diabetes mellitus, the cumulative risk of one lo wer-extremity amputation was 11.2% in insulin-dependent diabetes melli tus and 11.0% in non-insulin-dependent diabetes mellitus. When compare d with lower-extremity amputation rates for Rochester residents withou t diabetes, patients with non-insulin-dependent diabetes mellitus were nearly 400 times more likely to undergo an initial transphalangeal am putation (rate ratio, 378.8) and had almost a 12-fold increased risk o f a below-knee amputation (rate ratio, 11.8). In this community, more than 60% of lower-extremity amputations were attributable to non-insul in-dependent diabetes mellitus. Conclusions: These population-based da ta document the magnitude of the elevated risk of lower-extremity ampu tation among diabetic individuals. Efforts should be made to identify more precisely risk factors for amputation in diabetes and to interven e in the processes leading to amputation.