Impacts of evidence-based quality improvement on depression in primary care: a randomized experiment

Abstract

Context: Previous studies testing continuous quality improvement (CQI) for depression showed no effects. Methods for practices to self-improve depression care performance are needed. We assessed the impacts of evidence-based quality improvement (EBQI), a modification of CQI, as carried out by 2 different health care systems, and collected qualitative data on the design and implementation process.

Objective: Evaluate impacts of EBQI on practice-wide depression care and outcomes.

Design: Practice-level randomized experiment comparing EBQI with usual care.

Setting: Six Kaiser Permanente of Northern California and 3 Veterans Administration primary care practices randomly assigned to EBQI teams (6 practices) or usual care (3 practices). Practices included 245 primary care clinicians and 250,000 patients.

Intervention: Researchers assisted system senior leaders to identify priorities for EBQI teams; initiated the manual-based EBQI process; and provided references and tools. EVALUATION PARTICIPANTS: Five hundred and sixty-seven representative patients with major depression.

Main outcome measures: Appropriate treatment, depression, functional status, and satisfaction.

Results: Depressed patients in EBQI practices showed a trend toward more appropriate treatment compared with those in usual care (46.0% vs 39.9% at 6 months, P = .07), but no significant improvement in 12-month depression symptom outcomes (27.0% vs 36.1% poor depression outcome, P = .18). Social functioning improved significantly (mean score 65.0 vs 56.8 at 12 months, P = .02); physical functioning did not.

Conclusion: Evidence-based quality improvement had perceptible, but modest, effects on practice performance for patients with depression. The modest improvements, along with qualitative data, identify potential future directions for improving CQI research and practice.

FIGURE 1

MHAP intervention and evaluation design and timeline as implemented.^{‡ *}Zero indicates the start of the intervention. The overall timeline ranges from −6 months (start of the preintervention survey) to 30 months. ^†The callouts at the left hand side of the figure identify the design, Plan-Do-Study-Act (PDSA) and implementation phases of evidence-based quality improvement (EBQI). The EBQI design call-out represents the study intervention (researchers initiated and structured the EBQI design process in the experimental practices). ^‡The three-dimensional boxes in the diagram represent patient populations. Numbers (n) of patients for the pre and postintervention samples are listed on the appropriate boxes. • In the experimental practices, the white box labeled “depressed patients exposed to care model” represents patients exposed to the new depression care models developed by QI teams (e.g., seen by a depression care manager), whether or not they were enrolled in the postintervention survey sample, and contrasts with all unexposed depressed patients visiting experimental practices (vertical stripes). Note: we do not know what proportion was exposed. • The boxes labeled “longitudinal survey sample” represent patients enrolled in the postintervention evaluation. In experimental practices, the enrolled patients exposed to new care models (white area) contrast with the proportion not exposed (vertically striped area). ^§The time period labeled “exposure” indicates the mean duration of the window (i.e., between 8 and 12 months) during which patients who visited an intervention practice before their enrollment in the longitudinal survey sample might have been exposed to the new care models.