Diabetes and Lower-Limb Amputations in the Community: A retrospective cohort study

Abstract

OBJECTIVE There are few U.K. data on the incidence rates of amputation in diabetic subjects compared with the nondiabetic population. RESEARCH DESIGN AND METHODS We performed a historical cohort study of first lower-extremity amputations based in Tayside, Scotland (population 364,880) from 1 January 1993 to 31 December 1994. The Diabetes Audit and Research in Tayside Scotland (DARTS) database was used to identify a prevalence cohort of 7,079 diabetic patients on 1 January 1993. We estimated age-specific and standardized incidence rates of lower-limb amputations in the diabetic and nondiabetic cohorts. Results were compared with a previous study that evaluated lower-extremity amputations in diabetic patients in Tayside in 1980–1982. RESULTS There were 221 subjects who underwent a total of 258 nontraumatic amputations. Of the 221 subjects, 60 (27%) patients were diabetic (93% NIDDM), and 63% were first amputations. The median duration of diabetes was 6 years (range: newly diagnosed to 41 years). Nonhealing ulceration (31%) and gangrene (29%) were the two main indications for amputation in the diabetic subjects. Of the 161 nondiabetic subjects, 140 (80%) underwent first amputations. The adjusted incidences in the diabetic and nondiabetic groups were 248 and 20 per 100,000 person-years, respectively. Tayside patients with diabetes thus had a 12.3-fold risk of an amputation compared with nondiabetic residents (95% Cl 8.6–17.5). The estimated proportion of diabetic patients in the population rose from 0.81% in 1980–1982 to 1.94% in 1993–1994, whereas the absolute rate of amputation in diabetic subjects was unchanged from that in 1980–1982. CONCLUSIONS These population-based U.K. amputation data are similar to amputation rates in the U.S. Amputation rates appear to have decreased significantly since 1980–1982. The impact of diabetes education and prevention programs that target the processes leading to amputation can now be evaluated.