Abstract
BACKGROUND: Depression is common among primary care patients in LMIC but treatments are largely ineffective. In this cluster-randomized controlled trial, we tested whether depression outcomes are different among recipients of a collaborative care model compared to enhanced standard treatment in patients with co-morbid chronic medical conditions. METHODS: We conducted a cluster randomized controlled trial among participants 30 years or older seeking care at 49 primary health centers (PHCs) in rural Karnataka, diagnosed with major depressive disorder, dysthymia, generalized anxiety disorder, or panic disorder on the MINI-International Neuropsychiatric Interview plus either hypertension, diabetes, or ischemic heart disease. From a list of all PHCs in the district, 24 PHCs were randomized a priori to deliver collaborative care and 25 PHCs enhanced standard treatment. The collaborative care model consisted of a clinic-based and a community-based component. Study assessment staff was blinded to treatment arm allocation. The primary outcome was the individual-level PHQ-9 score over time. RESULTS: Between May 2015 and Nov 2018, 2486 participants were enrolled, 1264 in the control arm, and 1222 in the intervention arm. They were assessed at baseline, 3, 6 and 12 months. The mean PHQ-9 depression score was around 8.5 at baseline. At each follow-up PHQ-9 scores were significantly lower in the intervention (5.24, 4.81 and 4.22 at respective follow-ups) than in the control group (6.69, 6.13, 5.23, respectively). A significant time-by-treatment interaction (p < 0.001) in a multi-level model over all waves, nested within individuals who were nested within PHCs, confirmed that the decrease in depression score from baseline was larger for collaborative care than enhanced standard care throughout follow-up. CONCLUSIONS: The collaborative care intervention resulted in significantly lower depression scores compared to enhanced standard care among participants with co-morbid physical conditions. The findings have potential implications for integrating mental health and chronic disease treatment in resource constrained settings. TRIAL REGISTRATION: ClinicalTrials.gov NCT02310932 , registered on December 8, 2014, and Clinical Trials Registry India CTRI/2018/04/013001 , registered on April 4, 2018. Retrospectively registered.