Incidence of lower limb amputations and diabetes.

Objective: We collected data on the incidence rates of amputations and their relative risk in diabetic subjects compared with the nondiabetic population.
Research Design and Methods: From all three hospitals in a city of approximately 160,000 inhabitants, we obtained complete lists of nontraumatic lower limb amputations. From each patient record, diabetic status was determined. We estimated age-specific and standardized incidence rates of amputations in the diabetic and nondiabetic populations and in the entire population, as well as the relative and attributable risks due to diabetes.
Results: Nontraumatic lower limb amputations were performed on 106 residents of Leverkusen (Germany) in 1990 and 1991. Of them, 82 (77.4%) had diabetes. Mean age was 72.0 years. In the case of multiple amputations, only the highest level was counted for the analysis. The following results were standardized to the German population. Incidence rates (100,000(-1) year-1) were determined to be as follows: for all amputations per total population, 33.8; for amputations in diabetic individuals per diabetic population, 209.2; for amputations in nondiabetic individuals per nondiabetic population, 9.4. Relative risk was 22.2; attributable risk among exposed, 0.96; population attributable risk, 0.72. When the study is repeated to monitor the St. Vincent targets (50% reduction), a reduction in the amputation rate in the diabetic population by 46% will be detected with 90% power.
Conclusions: We found incidence rates similar to those in the non-Indian population of the U.S. Great relative and population-attributable risks indicate that improving foot care in diabetic individuals appears to be the main target for the reduction of amputations in the general population.