The effect of risk and race on lower extremity amputations among Medicare diabetic patients

The effect of national quality initiatives aiming at limiting lower extremity amputations in diabetic patients remains uncertain. We therefore explored trends in amputation among Medicare diabetic patients with a focus on those at highest risk.

The Diabetes Analytical File, an enhanced sample of all diabetic patients from the Medicare 5% sample, was used to study the national incidence of amputation in diabetic patients. Within a cohort of ∼5 million diabetic patients between 1999 and 2006, we compared the incidence of amputation in high-risk (end-stage renal disease or more than three comorbidities) and low-risk groups and by race.

Between 1999 and 2006, 23,976 amputations were performed, comprising 11,558 in high-risk and 12,418 in low-risk patients. The amputation rate declined over time from 4.8/1000 in 1999 to 4.4/1000 in 2006 (P<.001). High-risk patients represented a growing proportion of all amputations (33% in 1999, 50% in 2006; P<.001) despite representing 4% of diabetic patients in 1999 and 10% in 2006 (P<.001). The incidence of amputation was 29.6/1000 in the high-risk group vs 2.7/1000 in low-risk patients (P<.001). African Americans had higher rates of amputation in high-risk and low-risk groups.

High-risk patients represent a minority of Medicare diabetic patients but account for 50% of all amputations, and this effect is magnified in African Americans. Future quality improvement efforts should focus on high-risk patients and African Americans.