title: Closing the quality gap: revisiting the state of the science (vol. 2: the patient-centered medical home).
abstract: OBJECTIVE
  As part of the Closing the Quality Gap: Revisiting the State of the Science series of the Agency for Healthcare Research and Quality (AHRQ), this systematic review sought to identify completed and ongoing evaluations of the comprehensive patient-centered medical home (PCMH), summarize current evidence for this model, and identify evidence gaps.
  
  
  METHODS
  We searched PubMed®, CINAHL®, and the Cochrane Database of Systematic Reviews for published English-language studies, and a wide variety of databases and Web resources to identify ongoing or recently completed studies.
  
  
  METHODS
  Two investigators per study screened abstracts and full-text articles for inclusion, abstracted data, and performed quality ratings and evidence grading. Our functional definition of PCMH was based on the definition used by AHRQ. We included studies that explicitly claimed to be evaluating PCMH and those that did not but which met our functional definition.
  
  
  RESULTS
  Seventeen studies with comparison groups evaluated the effects of PCMH (Key Question [KQ] 1). Older adults in the United States were the most commonly studied population (8 of 17 studies). PCMH interventions had a small positive impact on patient experiences (including patient-perceived care coordination) and small to moderate positive effects on preventive care services (moderate strength of evidence [SOE]). Staff experiences were also improved by a small to moderate degree (low SOE). There were too few studies to estimate effects on clinical or most economic outcomes. Twenty-one of 27 studies reported approaches that addressed all 7 major PCMH components (KQ 2), including team-based care, sustained partnership, reorganized care or structural changes to care, enhanced access, coordinated care, comprehensive care, and a systems-based approach to quality. A total of 51 strategies were used to address the 7 major PCMH components. Twenty-two of 27 studies reported information on financial systems used to implement PCMH, implementation strategies, and/or organizational learning strategies for implementing PCMH (KQ 3). The 31 studies identified in the horizon scan of ongoing PCMH studies (KQ 4) were broadly representative of the U.S. health care system, both in geography and in the complexity of private and public health care payers and delivery networks.
  
  
  CONCLUSIONS
  Published studies of PCMH interventions often have similar broad elements, but precise components of care varied widely. The PCMH holds promise for improving the experiences of patients and staff, and potentially for improving care processes. However, current evidence is insufficient to determine effects on clinical and most economic outcomes. Ongoing studies identified through the horizon scan have potential to greatly expand the evidence base relating to PCMH.
authors.forename: John W
authors.initials: JW
authors.lastname: Williams
authors.forename: George L
authors.initials: GL
authors.lastname: Jackson
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Powers
authors.forename: Ranee
authors.initials: R
authors.lastname: Chatterjee
authors.forename: Janet Prvu
authors.initials: JP
authors.lastname: Bettger
authors.forename: Alex R
authors.initials: AR
authors.lastname: Kemper
authors.forename: Vic
authors.initials: V
authors.lastname: Hasselblad
authors.forename: Rowena J
authors.initials: RJ
authors.lastname: Dolor
authors.forename: R Julian
authors.initials: RJ
authors.lastname: Irvine
authors.forename: Brooke L
authors.initials: BL
authors.lastname: Heidenfelder
authors.forename: Amy S
authors.initials: AS
authors.lastname: Kendrick
authors.forename: Rebecca
authors.initials: R
authors.lastname: Gray
mesh_terms: D006801:Humans; D010348:Patient Care Team; D018802:Patient-Centered Care; D011314:Preventive Health Services; D011787:Quality of Health Care