Quality Improvement for Depression in Primary Care: Do Patients With Subthreshold Depression Benefit in the Long Run?

OBJECTIVE: Quality improvement programs for depression can improve outcomes, but the utility of including patients with subthreshold depression in quality improvement programs is unclear. The authors examined 57-month effects of quality improvement on clinical outcomes and mental health care utilization of primary care patients with depressive disorder and subthreshold depression. METHOD: In a group-level, randomized, controlled trial, 46 primary care clinics were randomly assigned to provide usual care or care with a quality improvement intervention that included provider training and other resources for either medication management (medications quality improvement) or evidence-based psychotherapy (therapy quality improvement). Among 1,356 enrolled depressed patients, 991 completed the 57-month follow-up interview (604 patients with depressive disorder and 387 with subthreshold depression). Outcomes measured at 57 months were presence of probable depressive disorder, unmet need for appropriate care (untreated probable disorder), and mental health care utilization in the prior 6 months. RESULTS: Among patients with subthreshold depression at baseline, those seen in clinics with quality improvement programs with special resources for therapy were less likely to have probable depressive disorder and unmet need for care at follow-up, compared with those seen in clinics that provided usual care. Among patients with depressive disorder at baseline, those seen in clinics with quality improvement programs with special resources for medication management were less likely to have unmet need for care at follow-up, compared with those seen in clinics that provided usual care. Patients with subthreshold depression at baseline seen in clinics with a quality improvement intervention were less likely at follow-up to have had a mental health visit (in primary care or specialty care, depending on the intervention) in the prior 6 months. CONCLUSIONS: Relative to usual care, quality improvement interventions improved 57-month outcomes (probable depression, unmet need, or both) for primary care patients with depressive disorder and subthreshold depression and lowered use of mental health visits for those with subthreshold depression. The results highlight the feasibility and utility of including patients with subthreshold depression in such programs.