THE COST IMPLICATIONS OF SHARED DECISION MAKING USING DECISION AIDS: A META-ANALYSIS AND CRITICAL APPRAISAL OF THE LITERATURE

Purpose: There is growing interest in promoting shared decision making (SDM) to increase patient participation in health care and to contain health care costs.  We sought to estimate the impact of SDM on health care utilization and costs by conducting a meta-analysis of randomized controlled trials measuring the costs of SDM.

Method: We searched the Cochrane database on decision aids and MEDLINE computerized databases (1950 to October 2009) and manually reviewed reference lists from original communications, review articles, and chapters.  Only randomized controlled trials that reported costs associated with introducing one or more SDM interventions were included. We compared the total costs per patient per year in the SDM intervention versus control arm.  All costs were converted to 2008 $US/year.

Result: 723 abstracts were identified; 5 trials met inclusion criteria.  Four trials examined the impact of patient decision aids (DA), one tested the impact of a physician-targeted SDM educational program.  All trials were conducted in Europe.  Average follow-up time was 11.4 months (range 3- 24 months).  The mean proportion of patients who were willing to participate in a RCT of DA was 70% (range 51%-79%), and study drop out after randomization ranged from 8.3% to 30.1%. Participation rates for providers was lower than that for patients (9.5%)--with a higher drop out rate (55.6%). All trials used simple cost accounting techniques.  A meta-analysis of the total costs associated with SDM found that SDM increased health care costs by $164.29/patient/year (95% CI, -$298.72, $627.30).  None of the trials included in these analyses included the costs of identifying or screening subjects appropriate for SDM, updating the DA, nor implementing the DA in clinic; many excluded the costs of distributing the DA to patients or providers, of training providers in  SDM, and additional time spent with a health care provider.

Conclusion: Even though SDM tends to decrease the use of elective procedures and treatments, it increases total health care costs.  The true cost of SDM using DA is likely substantially higher than our estimate because many cost elements were not included in these studies. These findings emphasize the importance of exploring other approaches to introducing SDM in clinical care that may be more cost-effective, and the need to conduct rigorous cost effectiveness studies of SDM approaches.