title: A meta-analysis of interventions to improve care for chronic illnesses.
abstract: OBJECTIVE
  To use empirical data from previously published literature to address 2 research questions: (1) Do interventions that incorporate at least 1 element of the Chronic Care Model (CCM) result in improved outcomes for specific chronic illnesses? (2) Are any elements essential for improved outcomes?
  
  
  METHODS
  Meta-analysis.
  
  
  METHODS
  Articles were identified from narrative literature reviews and quantitative meta-analyses, each of which covered multiple bibliographic databases from inception to March 2003. We supplemented this strategy by searching the MEDLINE database (1998-2003) and by consulting experts. We included randomized and nonrandomized controlled trials of interventions that contained 1 or more elements of the CCM for asthma, congestive heart failure (CHF), depression, and diabetes. We extracted data on clinical outcomes, quality of life, and processes of care. We then used random-effects modeling to compute pooled standardized effect sizes and risk ratios.
  
  
  RESULTS
  Of 1345 abstracts screened, 112 studies contributed data to the meta-analysis: asthma, 27 studies; CHF, 21 studies; depression, 33 studies; and diabetes, 31 studies. Interventions with at least 1 CCM element had consistently beneficial effects on clinical outcomes and processes of care across all conditions studied. The effects on quality of life were mixed, with only the CHF and depression studies showing benefit. Publication bias was noted for the CHF studies and a subset of the asthma studies.
  
  
  CONCLUSIONS
  Interventions that contain at least 1 CCM element improve clinical outcomes and processes of care--and to a lesser extent, quality of life--for patients with chronic illnesses.
authors.affiliation: Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, WG-57 10900 Euclid Avenue, Cleveland, OH 44106-4945, USA. act2@case.edu
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Tsai
authors.forename: Sally C
authors.initials: SC
authors.lastname: Morton
authors.forename: Carol M
authors.initials: CM
authors.lastname: Mangione
authors.forename: Emmett B
authors.initials: EB
authors.lastname: Keeler
mesh_terms: D002908:Chronic Disease / Q000628:therapy*; D019317:Evidence-Based Medicine; D006801:Humans; D011787:Quality of Health Care; D014481:United States