Time to remission for depression with collaborative care management (CCM) in primary care

Background: Collaborative care management (CCM) has been shown to have superior outcomes to usual care (UC) for depressed patients with a fixed end point. This study was a survival analysis over time comparing CCM with UC using remission (9-item Patient Health Questionnaire [PHQ-9] score <5) and persistent depressive symptoms (PDSs; PHQ-9 score >10) as end points. Methods: A retrospective cohort study of 7340 patients with depression cared for at 4 outpatient primary care clinics was conducted from March 2008 through June 2013. All adult patients diagnosed with depression (International Classification of Diseases, 9th Revision [ICD-9], codes 296.2-3) or dysthymia (ICD-9 code 300.4) with an initial PHQ-9 score >10 were included. CCM was implemented at all clinics between 2008 and 2010. Kaplan-Meyer survival curves for time to remission and PDSs were plotted. A Cox proportional hazards model was used to adjust for expected differences between patients choosing CCM versus UC. Results: Median time to remission was 86 days (95% confidence interval [CI], 81-91 days) for the CCM group versus 614 days (95% CI, 565-692 days) for the UC group. Likewise, median duration of PDSs was 31 days (95% CI, 30-33 days) for the CCM group versus 154 days (95% CI, 138-182 days) for the UC group. In the Cox proportional hazards model, which controlled for covariates such as age, sex, race, diagnosis, and initial PHQ-9 score, CCM was associated with faster remission (hazard ratio of the CCM group [HRCCM], 2.48; 95% CI, 2.31-2.65). Conclusions: This study demonstrated that patients enrolled in CCM have a faster rate of remission and a shorter duration of PDSs than patients choosing UC.