Early Evidence on the Patient-Centered Medical Home

Purpose: The patient-centered medical home (PCMH, or medical home) aims to reinvigorate primary care and achieve the triple aim of better quality, lower costs, and improved experience of care. This study systematically reviews the early evidence on effectiveness of the PCMH. Methods: Out of 498 studies published or disseminated from January 2000 through September 2010 on U.S.-based interventions, 14 evaluations of 12 interventions met our inclusion criteria: the evaluation (1) tested a primary-care, practice-based intervention with three or more of five key PCMH principles and (2) used quantitative methods to examine effects on either (a) a triple aim outcome (quality of care, costs (or hospital use or emergency department use, two major cost drivers), and patient and caregiver experience) or (b) health care professional experience. We use a formal rating system to identify interventions that were evaluated using rigorous methods and synthesize the evidence from these evaluations. We also provide guidance to inform current efforts and structure future evaluations to maximize learning. Results: The results indicate that we need more evaluations of the medical home to assess and refine the model. The Joint Principles that first defined the PCMH were released in 2007, and we reviewed evidence through September 2010. Reflecting the time required to evaluate and publish findings on the model, the interventions most often cited in support of the medical home can be viewed as precursors to the medical home. While the interventions varied, most essentially tested the addition of a care manager operating from within the primary care practice rather than a fundamentally transformed practice. Most interventions were evaluated in practices that were part of larger delivery systems and targeted patients who were older and sicker than average. Turning to the evaluations, less than half assessed all triple aim outcomes. Evaluations of 6 of the 12 interventions provide rigorous evidence on one or more outcomes. This evidence indicates some favorable effects on all three triple aim outcomes, a few unfavorable effects on costs, and mostly inconclusive results (because of insufficient sample sizes to detect effects that exist or uncertain statistical significance of results because analyses did not account for clustering of patients within practices). Conclusions: Improving primary care is the lynchpin of achieving the triple aim outcomes. The PCMH is a promising innovation, and the model is rapidly evolving. Stronger evaluations are needed to provide guidance on how to refine and target the model to ensure that the substantial efforts of practices and payers needed to adopt the model are most effective.