The Cumulative Effects of Quality Improvement for Depression on Outcome Disparities Over 9 Years: Results From a Randomized, Controlled Group-Level Trial

Background:Quality improvement (QI) programs for depression can improve outcomes of care and reduce outcome disparities; but cumulative effects on mental health outcome disparities have seldom been evaluated. Objective:To estimate cumulative effects over many years of short-term QI programs for depression in primary care on mental health outcome disparities, and to develop an interpretation for annualized, cumulative mental health outcome scores. Design:We conducted a group-level, randomized controlled trial in 6 US healthcare organizations. The QI programs supported provider and patient education in depression treatment and resources for medication management (QI-Meds) or access to evidence-based psychotherapy (QI-Therapy). Sites were selected to oversample minorities. Patients:Results were extrapolated to 1188 initially enrolled and living patients depressed at baseline. Main Outcome:Psychologic well-being (MHI-5) estimated as cumulative outcomes and outcome disparities (minority-whites) over 9 years, and annualized. Results:Across analyses there was a significant interaction of intervention status and ethnicity [lowest F(2,160) = 4.96, P = 0.008]. QI-therapy improved cumulative outcomes among minorities (mean, 37.92–44.29 MHI-5 points) and reduced outcome disparities for the whole sample relative to usual care (UC) (by mean, 39.44–59.01 MHI-5 points) and relative to QI-Meds (by mean, 53.90–74.41 MHI-5 points), lowest t(103) = 3.12, P = 0.002. By comparison, UC patients who lost a loved one in the year after baseline had lower psychologic well being by 6.18 MHI-5 scale points compared with similar UC patients without such a loss [t(15)=2.52, P = 0.02]. Conclusions:QI programs incorporating support for evidence-based psychotherapy offer an approach to substantially reduce cumulative outcome disparities for depressed primary care patients.