title: Activity-based funding of hospitals and its impact on mortality, readmission, discharge destination, severity of illness, and volume of care: a systematic review and meta-analysis.
abstract: BACKGROUND
  Activity-based funding (ABF) of hospitals is a policy intervention intended to re-shape incentives across health systems through the use of diagnosis-related groups. Many countries are adopting or actively promoting ABF. We assessed the effect of ABF on key measures potentially affecting patients and health care systems: mortality (acute and post-acute care); readmission rates; discharge rate to post-acute care following hospitalization; severity of illness; volume of care.
  
  
  METHODS
  We undertook a systematic review and meta-analysis of the worldwide evidence produced since 1980. We included all studies reporting original quantitative data comparing the impact of ABF versus alternative funding systems in acute care settings, regardless of language. We searched 9 electronic databases (OVID MEDLINE, EMBASE, OVID Healthstar, CINAHL, Cochrane CENTRAL, Health Technology Assessment, NHS Economic Evaluation Database, Cochrane Database of Systematic Reviews, and Business Source), hand-searched reference lists, and consulted with experts. Paired reviewers independently screened for eligibility, abstracted data, and assessed study credibility according to a pre-defined scoring system, resolving conflicts by discussion or adjudication.
  
  
  RESULTS
  Of 16,565 unique citations, 50 US studies and 15 studies from 9 other countries proved eligible (i.e. Australia, Austria, England, Germany, Israel, Italy, Scotland, Sweden, Switzerland). We found consistent and robust differences between ABF and no-ABF in discharge to post-acute care, showing a 24% increase with ABF (pooled relative risk  = 1.24, 95% CI 1.18-1.31). Results also suggested a possible increase in readmission with ABF, and an apparent increase in severity of illness, perhaps reflecting differences in diagnostic coding. Although we found no consistent, systematic differences in mortality rates and volume of care, results varied widely across studies, some suggesting appreciable benefits from ABF, and others suggesting deleterious consequences.
  
  
  CONCLUSIONS
  Transitioning to ABF is associated with important policy- and clinically-relevant changes. Evidence suggests substantial increases in admissions to post-acute care following hospitalization, with implications for system capacity and equitable access to care. High variability in results of other outcomes leaves the impact in particular settings uncertain, and may not allow a jurisdiction to predict if ABF would be harmless. Decision-makers considering ABF should plan for likely increases in post-acute care admissions, and be aware of the large uncertainty around impacts on other critical outcomes.
authors.affiliation: Faculty of Health Sciences and Faculty of Science Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Karen S
authors.initials: KS
authors.lastname: Palmer
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada; Divisions of General Internal Medicine and Clinical Epidemiology, University Hospitals of Geneva and Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Agoritsas
authors.affiliation: Department of Family and Community Medicine, Department of Health Policy Management and Evaluation, University of Toronto and Medical Affairs and Health Systems Solutions at Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: Danielle
authors.initials: D
authors.lastname: Martin
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Taryn
authors.initials: T
authors.lastname: Scott
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Sohail M
authors.initials: SM
authors.lastname: Mulla
authors.affiliation: Memorial University of Newfoundland, St. John's, Newfoundland, Canada.
authors.forename: Ashley P
authors.initials: AP
authors.lastname: Miller
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Arnav
authors.initials: A
authors.lastname: Agarwal
authors.affiliation: Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Bresnahan
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Afeez Abiola
authors.initials: AA
authors.lastname: Hazzan
authors.affiliation: Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Jeffery
authors.affiliation: Paediatric Outcome Research Team, The Hospital for Sick Children, Toronto, Ontario, Canada and Division of General Pediatrics, University Hospitals of Geneva and Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Merglen
authors.affiliation: Rehabilitation School, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Negm
authors.affiliation: Department of General Internal Medicine, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Reed A
authors.initials: RA
authors.lastname: Siemieniuk
authors.affiliation: Health Sciences Library, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Neera
authors.initials: N
authors.lastname: Bhatnagar
authors.affiliation: St. Michael's Hospital, Department of Medicine and Institute of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Irfan A
authors.initials: IA
authors.lastname: Dhalla
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada; McMaster Health Forum, Centre for Health Economics and Policy Analysis, Department of Political Science, McMaster University, Hamilton, Ontario, Canada and Department of Global Health and Population, Harvard School of Public Health, Boston, Massachusetts, United States of America.
authors.forename: John N
authors.initials: JN
authors.lastname: Lavis
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: John J
authors.initials: JJ
authors.lastname: You
authors.affiliation: Grattan Institute, Carlton, Victoria, Australia.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Duckett
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Gordon H
authors.initials: GH
authors.lastname: Guyatt
mesh_terms: D003695:Delivery of Health Care; D003953:Diagnosis-Related Groups; D017052:Hospital Mortality; D006761:Hospitals; D006801:Humans; D016017:Odds Ratio; D010351:Patient Discharge; D010359:Patient Readmission; D012720:Severity of Illness Index