Cost-Effectiveness Evaluation of Collaborative Care for Diabetes and Depression in Primary Care.

INTRODUCTION: Information is limited on the cost effectiveness of strategies to improve depressive symptoms in patients with Type 2 diabetes in primary care outside of the U.S. METHODS: Using patient data from a 12-month controlled implementation trial, outcomes and healthcare costs determined through administrative database linkages were compared for a strategy of family physician notification and follow-up ("enhanced care") versus collaborative care. Two measures of effectiveness were used: depression-free days (DFDs) based on Patient Health Questionnaire, and quality-adjusted life years (QALYs) based on EQ-5D. Data were collected November 2010 to January 2013 with analyses completed in May 2015. Incremental cost-effectiveness ratios were also compared against true usual care patients. RESULTS: Among 227 patients, mean age was 58 years, 55% were female, and mean diabetes duration was 12 years. Compared with total 12-month cost per usual care patient (C$5,889), the incremental cost was C$450 for patients in enhanced care and C$1,021 for collaborative care. Both enhanced and collaborative care strategies improved outcomes compared with usual care, with incremental DFDs of 65.9 and 117.6, and incremental QALYs of 0.006 and 0.042, respectively. Compared with enhanced care, collaborative care yielded incremental cost-effectiveness ratios of C$11/DFD and C$15,861/QALY. Compared with usual care, the incremental cost-effectiveness ratios were C$7/DFD or C$76,271/QALY for enhanced care and C$9/DFD or C$24,368/QALY for collaborative care. CONCLUSIONS: In primary care patients with Type 2 diabetes who screened positive for depression, physician notification and follow-up was a clinically effective strategy compared with usual care, but investing more resources in collaborative care yielded the most cost-effective strategy.