Depression treatment and diabetes risk: a 9-year follow-up study of the impact trial

Abstract

Objectives: To examine the effect of a collaborative care program for late-life depression on risk of diabetes among depressed, older adults. Method: We conducted a 9-year follow-up study of 160 older, primary care patients with a depressive disorder but without diabetes enrolled at the Indiana sites of the Improving Mood-Promoting Access to Collaborative Treatment (IMPACT) trial. Results: Surprisingly, the rate of incident diabetes in the collaborative care group (22/80 = 27.5%) was twice the rate observed in the usual care group (11/80 = 13.7%). Cox proportional hazards models adjusted for randomization status (HR = 1.94, p = .076), demographic factors (HR = 1.94, p = .075), and additionally for diabetes risk factors (HR = 1.73, p = .157) indicated that the risk of incident diabetes did not differ between the collaborative care and usual care groups, with collaborative care patients remaining at a nonsignificant increased risk. Conclusions: Our novel findings suggest that depression may not be a casual risk factor for diabetes and that depression treatment may be insufficient to reduce the excess diabetes risk of depressed, older adults.