Depression and incident lower limb amputations in veterans with diabetes

Abstract

Problem

Depression is associated with a higher risk of macrovascular and microvascular complications and mortality in diabetes, but whether depression is linked to an increased risk of incident amputations is unknown. We examined the association between diagnosed depression and incident non-traumatic lower limb amputations in veterans with diabetes.

Methods

This was a retrospective cohort study from 2000-2004 that included 531,973 veterans from the Diabetes Epidemiology Cohorts, a national Veterans Affairs (VA) registry with VA and Medicare data. Depression was defined by diagnostic codes or antidepressant prescriptions. Amputations were defined by diagnostic and procedural codes. We determined the HR and 95% CI for incident non-traumatic lower limb amputation by major (transtibial and above) and minor (ankle and below) subtypes, comparing veterans with and without diagnosed depression and adjusting for demographics, health care utilization, diabetes severity and comorbid medical and mental health conditions.

Results

Over a mean 4.1 years of follow-up, there were 1289 major and 2541 minor amputations. Diagnosed depression was associated with an adjusted HR of 1.33 (95% CI: 1.15–1.55) for major amputations. There was no statistically significant association between depression and minor amputations (adjusted HR 1.01, 95% CI: 0.90–1.13).

Conclusions

Diagnosed depression is associated with a 33% higher risk of incident major lower limb amputation in veterans with diabetes. Further study is needed to understand this relationship and to determine whether depression screening and treatment in patients with diabetes could decrease amputation rates.

Introduction

Depression is twice as common in patients with diabetes compared to patients without diabetes (Ali et al., 2006, Anderson et al., 2001) and is associated with the development of diabetes complications, including macrovascular disease (Black, Markides, & Ray, 2003), microvascular disease (Black et al., 2003, Roy et al., 2007, Roy et al., 2007) and death (Black et al., 2003, Katon et al., 2005; Katon, Fan, et al., 2008). It is unknown whether depression is associated with incident diabetic lower limb amputations. In one study, decreased mental health functioning in diabetes patients was associated with increased odds of major amputation in the following year, but depression was not specifically examined (Tseng et al., 2007). In 253 persons with their first diabetic foot ulcer, depressive symptoms were associated with increased mortality (Ismail, Winkley, Stahl, Chalder, & Edmonds, 2007), but amputation risk was not increased (Winkley, Stahl, Chalder, Edmonds, & Ismail, 2007). The goal of this study was to determine whether depression is associated with incident diabetic nontraumatic lower limb amputations.