title: Readmissions after carotid artery revascularization in the Medicare population.
abstract: BACKGROUND
  In appropriately selected patients with severe carotid stenosis, carotid revascularization reduces ischemic stroke. Prior clinical research has focused on the efficacy and safety of carotid revascularization, but few investigators have considered readmission as a clinically important outcome.
  
  
  OBJECTIVE
  The aims of this study were to examine frequency, timing, and diagnoses of 30-day readmission following carotid revascularization; to assess differences in 30-day readmission between patients undergoing carotid endarterectomy (CEA) and carotid artery stenting (CAS); to describe hospital variation in risk-standardized readmission rates (RSRR); and to examine whether hospital variation in the choice of procedure (CEA vs. CAS) is associated with differences in RSRRs.
  
  
  METHODS
  We used Medicare fee-for-service administrative claims data to identify acute care hospitalizations for CEA and CAS from 2009 to 2011. We calculated crude 30-day all-cause hospital readmissions following carotid revascularization. To assess differences in readmission after CAS compared with CEA, we used Kaplan-Meier survival curves and fitted mixed-effects logistic regression. We estimated hospital RSRRs using hierarchical generalized logistic regression. We stratified hospitals into 5 groups by their proportional CAS use and compared hospital group median RSRRs.
  
  
  RESULTS
  Of 180,059 revascularizations from 2,287 hospitals, CEA and CAS were performed in 81.5% and 18.5% of cases, respectively. The unadjusted 30-day readmission rate following carotid revascularization was 9.6%. Readmission risk after CAS was greater than that after CEA. There was modest hospital-level variation in 30-day RSRRs (median: 9.5%; range 7.5% to 12.5%). Variation in proportional use of CAS was not associated with differences in hospital RSRR (range of median RSRR across hospital groups 9.49% to 9.55%; p = 0.771).
  
  
  CONCLUSIONS
  Almost 10% of Medicare patients undergoing carotid revascularization were readmitted within 30 days of discharge. Compared with CEA, CAS was associated with a greater readmission risk. However, hospitals' RSRR did not differ by their proportional CAS use.
authors: Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
authors: Mohammed Salim
authors: MS
authors: Al-Damluji
authors: Center for Outcome Research and Evaluation, Yale University, New Haven, Connecticut; Division of Cardiology, Columbia University Medical Center, New York, New York.
authors: Kumar
authors: K
authors: Dharmarajan
authors: Center for Outcome Research and Evaluation, Yale University, New Haven, Connecticut.
authors: Weiwei
authors: W
authors: Zhang
authors: Center for Outcome Research and Evaluation, Yale University, New Haven, Connecticut.
authors: Lori L
authors: LL
authors: Geary
authors: Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut; Cardiovascular Division, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut.
authors: Erik
authors: E
authors: Stilp
authors: Yale University Vascular Biology and Therapeutics Program, New Haven, Connecticut; Department of Surgery, Yale University School of Medicine, New Haven, Connecticut; Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut.
authors: Alan
authors: A
authors: Dardik
authors: Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut; Cardiovascular Division, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut.
authors: Carlos
authors: C
authors: Mena-Hurtado
authors: Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut; Center for Outcome Research and Evaluation, Yale University, New Haven, Connecticut; Cardiovascular Division, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut. Electronic address: jeptha.curtis@yale.edu.
authors: Jeptha P
authors: JP
authors: Curtis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016893:Carotid Stenosis / Q000453:epidemiology* / Q000601:surgery*; D016894:Endarterectomy, Carotid / Q000639:trends*; D005260:Female; D006801:Humans; D008297:Male; D006278:Medicare / Q000639:trends*; D010359:Patient Readmission / Q000639:trends*; D011159:Population Surveillance / Q000379:methods; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology
keywords: carotid artery stenosis; carotid artery stenting; carotid endarterectomy; hospital readmission