Collaborative care management (CCM) for depression has been demonstrated to improve clinical outcomes. The impetus for this study was to determine if outpatient utilization patterns would be associated with depression outcomes. The hypothesis was that depression remission would be independently correlated with outpatient utilization at 6 and 12 months after enrollment into CCM. The study was a retrospective chart review analysis of 773 patients enrolled into CCM with 6- and 12-month follow-up data. The data set comprised baseline demographic data, patient intake self-assessment scores (Patient Health Questionnaire [PHQ-9], Generalized Anxiety Disorder-7, Mood Disorder Questionnaire, and Alcohol Use Disorders Identification Test), the number of outpatient visits, and follow-up PHQ-9 scores. To control for individual patient complexity and pattern of usage, the number of outpatient visits for 6 months prior to enrollment also was measured. With a logistic regression model for outpatient visit outlier status as the dependent variable, remission at 6 months (odds ratio [OR] 0.519, CI [confidence interval] 0.349-0.770, P=0.001) and remission at 12 months (OR 0.573, CI 0.354-0.927, P=0.023) were predictive. With this inverse relationship between remission and outlier status, those patients who were not in remission had an OR of 1.928 for outpatient visit outlier status at 6 months after enrollment and an OR of 1.745 at 12 months. Patients who improved clinically to remission while in CCM had decreased odds of outlier status for outpatient utilization at 6 and 12 months when controlling for all other study variables. Improvement in health care outcomes by CCM could translate into decreased outpatient utilization for depressed patients.

Increased odds of persistent depressive symptoms and increased number of outpatient visits were found in patients with depression and concomitant LBCs 6 months after enrollment into collaborative care management, compared with those in patients with depression and without LBCs. The data suggest that temporally related LBCs could lead to worse outcomes in primary care patients being treated for depression, encouraging closer observation and possible therapeutic changes in this cohort.