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 documented effectiveness in treating depression and anxiety disorders. The evidence for their efficacy against other mental disorders is limited. In this study, we evaluated 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 outpatient care setting in Germany.

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

Results: 41 primary care practices were randomized either to COMET (the CSC group, n = 20) or treatment as usual (the TAU group, n = 21). 615 patients were recruited (CSC: n = 307; TAU: n = 308). Data were available for 62% (CSC) and 55% (TAU) of the subjects at six months. No significant difference was found between groups with respect to the primary outcome (-1.96 [95% confidence interval: [-4.39; 0.48], p = 0.113) or any of the secondary outcomes.

Conclusion: We found no superiority of CSC in the treatment of the mental disorders addressed in this study. 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, with attention to factors of implementation.