Collaborative care versus screening and follow-up for patients with diabetes and depressive symptoms: results of a primary care-based comparative effectiveness trial.

Abstract

Depressive symptoms are common and, when coexisting with diabetes, worsen outcomes and increase health care costs. We evaluated a nurse case-manager-based collaborative primary care team model to improve depressive symptoms in diabetic patients. We conducted a controlled implementation trial in four nonmetropolitan primary care networks. Eligible patients had type 2 diabetes and screened positive for depressive symptoms, based on a Patient Health Questionnaire (PHQ) score of ≥10. Patients were allocated using an "on-off" monthly time series. Intervention consisted of case-managers working 1:1 with patients to deliver individualized care. The main outcome was improvement in PHQ scores at 12 months. A concurrent cohort of 71 comparable patients was used as nonscreened usual care control subjects. Of 1,924 patients screened, 476 (25%) had a PHQ score >10. Of these, 95 were allocated to intervention and 62 to active control. There were no baseline differences between groups: mean age was 57.8 years, 55% were women, and the mean PHQ score was 14.5 (SD 3.7). Intervention patients had greater 12-month improvements in PHQ (7.3 [SD 5.6]) compared with active-control subjects (5.2 [SD 5.7], P = 0.015). Recovery of depressive symptoms (i.e., PHQ reduced by 50%) was greater among intervention patients (61% vs. 44%, P = 0.03). Compared with trial patients, nonscreened control subjects had significantly less improvement at 12 months in the PHQ score (3.2 [SD 4.9]) and lower rates of recovery (24%, P < 0.05 for both). In patients with type 2 diabetes who screened positive for depressive symptoms, collaborative care improved depressive symptoms, but physician notification and follow-up was also a clinically effective initial strategy compared with usual care.