• cost-benefit analysis;
  • depression;
  • quality of life;
  • primary health care

OBJECTIVE: To determine the incremental cost-effectiveness of a quality improvement depression intervention (enhanced care) in primary care settings relative to usual care.

DESIGN: Following stratification, we randomized 12 primary care practices to enhanced or usual care conditions and followed patients for 12 months.

SETTING: Primary care practices located in 10 states across the United States.

PATIENTS/PARTICIPANTS: Two hundred eleven patients beginning a new treatment episode for major depression.

INTERVENTIONS: Training the primary care team to assess, educate, and monitor depressed patients during the acute and continuation stages of their depression treatment episode over 1 year.

MEASUREMENTS AND MAIN RESULTS: Cost-effectiveness was measured by calculating incremental (enhanced minus usual care) costs and quality-adjusted life years (QALYs) derived from SF-36 data. The mean incremental cost-effectiveness ratio in the main analysis was $15,463 per QALY. The mean incremental cost-effectiveness ratios for the sensitivity analyses ranged from $11,341 (using geographic block variables to control for pre-intervention service utilization) to $19,976 (increasing the cost estimates by 50%) per QALY.

CONCLUSIONS: This quality improvement depression intervention was cost-effective relative to usual care compared to cost-effectiveness ratios for common primary care interventions and commonly cited cost-effectiveness ratio thresholds for intervention implementation.