Cost-effectiveness of quality improvement programs for patients with subthreshold depression or depressive disorder.

OBJECTIVE: This study explored the cost-effectiveness of quality-improvement interventions for depression in primary care, relative to usual care, among patients with subthreshold depression or depressive disorder.

METHODS: A total of 746 primary care patients in managed care organizations with 12-month depressive disorder and 502 with current depressive symptoms but no disorder (subthreshold depression) participated in a group-level randomized controlled trial initiated between June 1996 and March 1997. Matched clinics were randomly assigned to enhanced usual care or one of two quality improvement interventions that provided education to manage depression over time and resources to facilitate access to medication management or psychotherapy for six to 12 months.

RESULTS: The cost-effectiveness ratio for the pooled intervention groups versus usual care was $2,028 for patients with subthreshold depression (95% confidence interval [CI]=-$17,225 to $21,282) and $53,716 for those with depressive disorder (CI=$14,194 to $93,238), by using a measure of quality-adjusted life years (QALY) based on the 12-Item Short Form Health Survey. Similar results were obtained when alternative QALY measures were used.

CONCLUSIONS: Although precision was limited, even the upper limit of the 95% CIs suggests that such interventions are as cost-effective for patients with subthreshold depression as are many widely used medical therapies. Despite lack of evidence for efficacy of treatments for subthreshold depression, disease management programs that support clinical care decisions over time for patients with subthreshold depression or depressive disorder can yield cost-effectiveness ratios comparable to those of widely adopted medical therapies. Achieving greater certainty about average cost-effectiveness would require a much larger study.