title: Impact of Race/Ethnicity and Socioeconomic Status on Risk-Adjusted Hospital Readmission Rates Following Hip and Knee Arthroplasty.
abstract: BACKGROUND
  Readmission rates following total hip arthroplasty (THA) and total knee arthroplasty (TKA) are increasingly used to measure hospital performance. Readmission rates that are not adjusted for race/ethnicity and socioeconomic status, patient risk factors beyond a hospital's control, may not accurately reflect a hospital's performance. In this study, we examined the extent to which risk-adjusting for race/ethnicity and socioeconomic status affected hospital performance in terms of readmission rates following THA and TKA.
  
  
  METHODS
  We calculated 2 sets of risk-adjusted readmission rates by (1) using the Centers for Medicare & Medicaid Services standard risk-adjustment algorithm that incorporates patient age, sex, comorbidities, and hospital effects and (2) adding race/ethnicity and socioeconomic status to the model. Using data from the Healthcare Cost and Utilization Project, 2011 State Inpatient Databases, we compared the relative performances of 1,194 hospitals across the 2 methods.
  
  
  RESULTS
  Addition of race/ethnicity and socioeconomic status to the risk-adjustment algorithm resulted in (1) little or no change in the risk-adjusted readmission rates at nearly all hospitals; (2) no change in the designation of the readmission rate as better, worse, or not different from the population mean at >99% of the hospitals; and (3) no change in the excess readmission ratio at >97% of the hospitals.
  
  
  CONCLUSIONS
  Inclusion of race/ethnicity and socioeconomic status in the risk-adjustment algorithm led to a relative-performance change in readmission rates following THA and TKA at <3% of the hospitals. We believe that policymakers and payers should consider this result when deciding whether to include race/ethnicity and socioeconomic status in risk-adjusted THA and TKA readmission rates used for hospital accountability, payment, and public reporting.
  
  
  METHODS
  Prognostic Level III. See instructions for Authors for a complete description of levels of evidence.
authors.affiliation: RAND Corporation, Pittsburgh, Pennsylvania martsolf@rand.org.
authors.forename: Grant R
authors.initials: GR
authors.lastname: Martsolf
authors.affiliation: M.L. Barrett, Inc., San Diego, California.
authors.forename: Marguerite L
authors.initials: ML
authors.lastname: Barrett
authors.affiliation: Truven Health Analytics, Inc., Santa Barbara, California.
authors.forename: Audrey J
authors.initials: AJ
authors.lastname: Weiss
authors.affiliation: RAND Corporation, Pittsburgh, Pennsylvania kandrack@rand.org.
authors.forename: Ryan
authors.initials: R
authors.lastname: Kandrack
authors.affiliation: Agency for Healthcare Research and Quality, Rockville, Maryland.
authors.forename: Raynard
authors.initials: R
authors.lastname: Washington
authors.affiliation: Agency for Healthcare Research and Quality, Rockville, Maryland.
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Steiner
authors.affiliation: RAND Corporation, Boston, Massachusetts Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts.
authors.forename: Ateev
authors.initials: A
authors.lastname: Mehrotra
authors.affiliation: Department of Orthopaedic Surgery, UCLA Medical Center, Los Angeles, California.
authors.forename: Nelson F
authors.initials: NF
authors.lastname: SooHoo
authors.affiliation: Truven Health Analytics, Inc., Bethesda, Maryland.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Coffey
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005006:Ethnicity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission / Q000706:statistics & numerical data*; D011183:Postoperative Complications / Q000209:etiology*; D018570:Risk Assessment; D012307:Risk Factors; D012923:Social Class; D012959:Socioeconomic Factors; D055815:Young Adult