Unpacking Collaborative Care for Depression: Examining Two Essential Tasks for Implementation.

Abstract

This study examined how two key process-of-care tasks of the collaborative care model (CCM) predict patient depression outcomes. Registry data were from a large implementation of the CCM in Washington State and included 5,439 patient-episodes for patients age 18 or older with a baseline Patient Health Questionnaire-9 (PHQ-9) score of ≥10 and at least one follow-up contact with the CCM care manager within 24 weeks of initial contact. Key CCM tasks examined were at least one care manager follow-up contact within four weeks of initial contact and at least one psychiatric consultation between weeks 8 and 12 for patients not responding to treatment by week 8. Clinically significant improvement in depression symptoms was defined as achieving a PHQ-9 score of <10 or a 50% or more reduction in PHQ-9 score compared with baseline. Bivariate and multivariate (logistic and proportional hazard models) analyses were conducted to examine how fidelity with either task predicted outcomes. All analyses were conducted with the original sample and with a propensity score-matched sample. Four-week follow-up was associated with a greater likelihood of achieving improvement in depression (odds ratio [OR]=1.63, 95% confidence interval [CI]=1.23-2.17) and a shorter time to improvement (hazard ratio=2.06, CI=1.67-2.54). Psychiatric consultation was also associated with a greater likelihood of improvement (OR=1.44, CI=1.13-1.84) but not with a shorter time to improvement. Propensity score-matched analysis yielded very similar results. Findings support efforts to improve fidelity to the two process-of-care tasks and to include these tasks among quality measures for CCM implementation.