Early Evaluations of the Medical Home: Building on a Promising Start

Findings from a systematic evidence review of the medical home are promising, but indicate the critical need for stronger evaluations to guide policy makers.
Published Online: February 27, 2012
Deborah Peikes, PhD; Aparajita Zutshi, PhD; Janice L. Genevro, PhD; Michael L. Parchman, MD; and David S. Meyers, MD
Objectives: To systematically review the current evidence on the patient-centered medical home (PCMH, or medical home), which aims to reinvigorate primary care and achieve the triple aim of better quality, improved experience, and lower costs.

Study Design: Systematic review of quantitative evidence on the PCMH.

Methods: Out of 498 studies published or disseminated from January 2000 to September 2010 on US-based interventions, 14 evaluations of 12 interventions met our inclusion criteria: (1) tested a practice-level intervention with 3 or more of 5 key PCMH components and (2) conducted a quantitative study of one of the triple aim outcomes or of healthcare professional experience. We synthesized fi ndings on interventions that were evaluated using rigorous methods. We also provide guidance to structure future evaluations to maximize learning.

Results: The interventions most often cited to support the medical home can be viewed as precursors to the medical home. Evaluations of 6 of these interventions provided rigorous evidence on 1 or more outcomes. This evidence indicates some favorable effects on all 3 triple aim outcomes, a few unfavorable effects on costs, and many inconclusive results.

Conclusions: Although the PCMH is a promising innovation, rigorous quantitative evaluations and comprehensive implementation analyses are needed to assess effectiveness and refi ne the model to meet stakeholders’ needs. Findings from future evaluations will help guide the substantial efforts practices and payers invest to adopt the PCMH with the goal of achieving the triple aim outcomes.

(Am J Manag Care. 2012;18(2):105-116)
This article summarizes the current evidence on the patient-centered medical home (PCMH) and provides concrete suggestions for conducting more rigorous evaluations. We found:

  • Most early evaluations tested precursors to the PCMH.

  • Among the 14 evaluations reviewed, 6 provide rigorous evidence on at least 1 of the 3 triple aim outcomes (better quality, improved experience, and lower costs) or healthcare professional experience.

  • Evidence indicates some favorable effects on all 3 triple aim outcomes, a few unfavorable effects on costs, and many inconclusive results.

  • More rigorous quantitative evaluations and comprehensive implementation analyses are needed to assess effectiveness and refi ne the model to meet stakeholders’ needs.
Reinventing primary care is a task that is “far too important to fail”1 and central to reforming healthcare delivery. The current healthcare system, with its incentives to furnish more care, has produced highly fragmented care that emphasizes specialty and acute care over coordination, patient centeredness, and population health management.2-6 Although 93% of Americans want one place or doctor that provides primary care and coordinates care with specialists, only half report having such an experience.7,8 The patientcentered medical home (PCMH) is a promising model that aims to reinvent primary care so that it is “accessible, continuous, comprehensive and coordinated and delivered in the context of family and community,”9 and, in so doing, improve the triple aim outcomes of quality, cost, and patient and family experience, as well as healthcare professional experience.

The medical home concept fi rst arose in the 1960s as a way of improving care for children with special needs, and policy interest outside of pediatrics grew over time.10 In 2007, primary care physician societies endorsed the joint principles of this primary care delivery model.9 Intrigued by the potential of the PCMH model, private insurers, major private and federal employers, provider organizations, Medicare, and state Medicaid agencies across the nation are rolling out pilots and demonstrations of different variants of the model. However, it will likely take many years before results of current evaluations become available. Transforming care will require recognizing and addressing many barriers to change using lessons from these evaluations.11


Against this backdrop, decision makers consider whether the evidence supporting the model is already strong enough to proceed with widespread adoption, or whether gathering additional evidence is warranted. To contribute to this discussion, the Agency for Healthcare Research and Quality (AHRQ) commissioned Mathematica Policy Research to systematically review quantitative evaluations of the medical home model to inform current efforts and provide guidance to structure future evaluations to maximize learning. Qualitative evaluations can provide powerful insights; however, we excluded them from this review because of our focus on outcomes and because evaluations rarely documented their implementation experiences. Given that interest in the model is recent, the expectation was that only precursors to the PCMH would have been evaluated so far. A longer paper provides a more detailed description of this review.12

The review limits synthesis of fi ndings to interventions evaluated using rigorous methods. While much can be learned from less rigorous, rapid-cycle evaluations of lowcost, individual components of the medical home, this review intends to fulfi ll stakeholders’ need for high-quality quantitative evidence on medical home interventions that test multiple components and are costly for payers and providers to implement.

Some readers may not consider an evidence review of the PCMH to be necessary, because they believe that the evaluations conducted to date, combined with the vast cross-sectional literature on the positive relationship between more primary care and better outcomes, provide suffi cient evidence to proceed with widespread adoption of the model. Others may feel that the model is being held to a higher standard than many clinical interventions that are currently being used without strong evidentiary support.

Historically, a number of promising healthcare interventionshave been shown not to actually work when evaluated using rigorous methods. For example, telephonic disease management seemed to address obvious problems in coordination and patient self-management, but a number of randomized trials showed many ineffective programs and pointed the way to refining the model to offer better integration with providers, more in-person contact, and careful focusing of efforts to

those most likely to benefit.13-15 Similarly, rigorous evidence regarding the effectiveness of the PCMH model and how best to refine it is critical given the substantial investments this model requires.

This review makes 2 important methodological contributions. First, we limited the review to multicomponent interventions by requiring interventions to contain at least 3 of the 5 components in AHRQ’s defi nition of the PCMH model. Earlier reviews typically included results from interventions with as few as 1 component. One group of researchers found that only 1 of the 33 studies they reviewed was of an intervention modeled after the medical home, with the remaining studies testing selected components.16 Three others each reviewed the literature on individual components of the medical home, such as team-based care, rather than reviewing multicomponent interventions that more closely resemble the PCMH model.17-19 Second, we limited the synthesis of the evidence to that generated by rigorous evaluations, which we assess using a systematic review. Three previous reviews did not consider the quality of the evidence.20-22 Two reviews conducted a limited assessment by focusing on either comparison group studies16 or peer-reviewed studies,22 but neither assessed the strength of the analytical methods used by the studies or excluded weaker studies from their syntheses of the evidence.


We began the review by fi rst identifying evaluations of interventions that met our inclusion criteria, then rating the rigor of these evaluations, and fi nally synthesizing the evidence on PCMH effectiveness using only rigorous evaluations.

Inclusion Criteria

We identifi ed 498 citations based on a search of published and gray literature from January 2000 to September 2010, inputs from experts in the fi eld, and a review of 100 relevant Web sites. Out of these citations, we selected 14 evaluations of 12 interventions that met the following criteria:

1. The evaluation tested a practice-level intervention in the United States with 3 or more of the 5 medical home components defi ned by AHRQ. AHRQ defines the PCMH as delivering care that is patient centered, comprehensive, coordinated, and accessible, and follows a systems-based approach to quality and safety. The defi nition (available at pcmh.ahrq.gov) also emphasizes the central role of health information technology, workforce development, and fundamental payment reform. It builds on the traditional definition of primary care established by the Institute of Medicine23 and Barbara Starfield24,25 and incorporates aspects of the expanded care model.26,27 It is similar to the defi nition of the medical home emphasis on team-based care.

2. The evaluation used quantitative methods to examine effects on either (1) a triple aim outcome (quality of care, costs [or hospital or emergency department use, 2 major cost drivers], and patient experience) or (2) healthcare professional experience (refl ecting its importance in transforming primary care).

The first criterion excludes 2 studies of medical home interventions—the American Academy of Family Practice’s National Demonstration Project, which is often cited in the medical home literature, and the Illinois Medical Home Project—because rather than testing the effect of a medical home, they tested the effect of facilitation of a medical home (helping practices to become medical homes versus practices becoming medical homes on their own).

Rating the Rigor of the Evaluations

We developed a systematic approach to assess the rigor of the evaluations conducted to generate evidence on PCMH effectiveness. We drew broadly from the US Preventive Services Task Force review methods.28 We also drew specifi c operational criteria from the What Works Clearinghouse review of educational interventions (which also typically use clustered designs like the many practice-level interventions reviewed here)29 and from an evidence review of home-visiting programs for families with pregnant women and children.30

Rather than give a global rating to each evaluation, we individually rated the internal validity of each analysis conducted as part of the evaluation as high, moderate, low, or excluded. We rated individual analyses because evaluations often used different designs, samples, and methods (and sometimes different subgroups of patients) to analyze different outcomes over varying follow-up periods. We did not factor generalizability (or external validity) into the rating because most interventions included in this review targeted a specifi c subset of primary care patients, were implemented in unique settings, and either purposefully selected practices or relied on them to volunteer; therefore, fi ndings from nearly all interventions have limited generalizability. We did, however, summarize the characteristics of patients and practice settings of rigorously evaluated interventions to alert decision makers to the possibility that fi ndings might differ in other contexts.

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