title: Variation in hospital-level risk-standardized complication rates following elective primary total hip and knee arthroplasty.
abstract: BACKGROUND
  Little is known about the variation in complication rates among U.S. hospitals that perform elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) procedures. The purpose of this study was to use National Quality Forum (NQF)-endorsed hospital-level risk-standardized complication rates to describe variations in, and disparities related to, hospital quality for elective primary THA and TKA procedures performed in U.S. hospitals.
  
  
  METHODS
  We conducted a cross-sectional analysis of national Medicare Fee-for-Service data. The study cohort included 878,098 Medicare fee-for-service beneficiaries, sixty-five years or older, who underwent elective THA or TKA from 2008 to 2010 at 3479 hospitals. Both medical and surgical complications were included in the composite measure. Hospital-specific complication rates were calculated from Medicare claims with use of hierarchical logistic regression to account for patient clustering and were risk-adjusted for age, sex, and patient comorbidities. We determined whether hospitals with higher proportions of Medicaid patients and black patients had higher risk-standardized complication rates.
  
  
  RESULTS
  The crude rate of measured complications was 3.6%. The most common complications were pneumonia (0.86%), pulmonary embolism (0.75%), and periprosthetic joint infection or wound infection (0.67%). The median risk-standardized complication rate was 3.6% (range, 1.8% to 9.0%). Among hospitals with at least twenty-five THA and TKA patients in the study cohort, 103 (3.6%) were better and seventy-five (2.6%) were worse than expected. Hospitals with the highest proportion of Medicaid patients had slightly higher but similar risk-standardized complication rates (median, 3.6%; range, 2.0% to 7.1%) compared with hospitals in the lowest decile (3.4%; 1.7% to 6.2%). Findings were similar for the analysis involving the proportion of black patients.
  
  
  CONCLUSIONS
  There was more than a fourfold difference in risk-standardized complication rates across U.S. hospitals in which elective THA and TKA are performed. Although hospitals with higher proportions of Medicaid and black patients had rates similar to those of hospitals with lower proportions, there is a continued need to monitor for disparities in outcomes. These findings suggest there are opportunities for quality improvement among hospitals in which elective THA and TKA procedures are performed.
authors.affiliation: UCSF Department of Orthopaedic Surgery, 500 Parnassus Avenue, MU 320W, San Francisco, CA 94143-0728. E-mail address: kevin.bozic@ucsf.edu.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Bozic
authors.affiliation: Yale New Haven Health Services Corporation/Center for Outcomes Research & Evaluation (YNHHSC/CORE), 1 Church Street, Suite 200, New Haven, CT 06510.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Grosso
authors.affiliation: Yale New Haven Health Services Corporation/Center for Outcomes Research & Evaluation (YNHHSC/CORE), 1 Church Street, Suite 200, New Haven, CT 06510.
authors.forename: Zhenqiu
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Yale New Haven Health Services Corporation/Center for Outcomes Research & Evaluation (YNHHSC/CORE), 1 Church Street, Suite 200, New Haven, CT 06510.
authors.forename: Craig S
authors.initials: CS
authors.lastname: Parzynski
authors.affiliation: Yale New Haven Health Services Corporation/Center for Outcomes Research & Evaluation (YNHHSC/CORE), 1 Church Street, Suite 200, New Haven, CT 06510.
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Suter
authors.affiliation: Yale New Haven Health Services Corporation/Center for Outcomes Research & Evaluation (YNHHSC/CORE), 1 Church Street, Suite 200, New Haven, CT 06510.
authors.forename: Harlan M
authors.initials: HM
authors.lastname: Krumholz
authors.affiliation: Keck School of Medicine, University of Southern California, 1520 San Pablo Street, Suite 2000, Los Angeles, CA 90033.
authors.forename: Jay R
authors.initials: JR
authors.lastname: Lieberman
authors.affiliation: Department of Orthopaedic Surgery, Mayo Clinic, 200 First Street S.W., Rochester, MN 55905.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Berry
authors.affiliation: Department of Orthopaedic Surgery, University of Texas Southwestern, 4005 Wingren, Irving, TX 75062.
authors.forename: Robert
authors.initials: R
authors.lastname: Bucholz
authors.affiliation: Centers for Medicare & Medicaid Services, 7500 Security Boulevard, Baltimore, MD 21244.
authors.forename: Lein
authors.initials: L
authors.lastname: Han
authors.affiliation: Centers for Medicare & Medicaid Services, 7500 Security Boulevard, Baltimore, MD 21244.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Rapp
authors.affiliation: Yale New Haven Health Services Corporation/Center for Outcomes Research & Evaluation (YNHHSC/CORE), 1 Church Street, Suite 200, New Haven, CT 06510.
authors.forename: Susannah
authors.initials: S
authors.lastname: Bernheim
authors.affiliation: Yale New Haven Health Services Corporation/Center for Outcomes Research & Evaluation (YNHHSC/CORE), 1 Church Street, Suite 200, New Haven, CT 06510.
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Drye
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D003430:Cross-Sectional Studies; D017558:Elective Surgical Procedures / Q000009:adverse effects; D005260:Female; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D006278:Medicare / Q000706:statistics & numerical data*; D011183:Postoperative Complications / Q000453:epidemiology; D014481:United States / Q000453:epidemiology