Collaborative and Stepped Care for Mental Disorders: Results of a Cluster-Randomized Controlled Trial in Outpatient Care (The COMET Study).

Abstract

Background: Collaborative and stepped care (CSC) models are recommended in guidelines because of their effectiveness in treating depression and anxiety disorders. The evidence for other mental disorders is, however, limited. The aim of this study was to evaluate the effectiveness of a collaborative and stepped care model (COMET) for patients with depressive, anxiety, somatoform, and/or alcohol-related disorders and related comorbidities in the routine care setting in Germany.

Methods: A prospective, cluster-randomized, controlled, parallelgroup superiority trial was conducted; the subjects were patients in primary care practices. The primary endpoint was the change in mental health-related quality of life, assessed with the SF-36 Mental Health Component Summary Score (MCS) at 6 months in the intention-to-treat population. The secondary endpoints were symptom severity, remission, and response.

Results: Forty-one primary care offices were randomized either to COMET (n = 20) or treatment as usual (TAU, n = 21), and 615 patients were recruited (CSC: n = 307; TAU: n = 308). Data were available for 62% (COMET) and 55% (TAU) of the participants at 6 months. No significant group difference was found with respect to the primary endpoint (-1.96 ,95% confidence interval [-4.39; 0.48], p = 0.113) or any of the secondary endpoints.

Conclusion: We found no superiority of the COMET model for the mental disorders addressed. Methodological issues, including differences at baseline and high dropout rates, make these findings challenging to interpret. Future studies should ensure comparability of groups, allocate resources for quality management, and investigate more suitable outcome measures, paying attention to factors of implementation.