title: Volume-based referral for cardiovascular procedures in the United States: a cross-sectional regression analysis.
abstract: BACKGROUND
  We sought to estimate the numbers of patients affected and deaths avoided by adopting the Leapfrog Group's recommended hospital procedure volume minimums for coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI). In addition to hospital risk-adjusted mortality standards, the Leapfrog Group recommends annual hospital procedure minimums of 450 for CABG and 400 for PCI to reduce procedure-associated mortality.
  
  
  METHODS
  We conducted a retrospective analysis of a national hospital discharge database to evaluate in-hospital mortality among patients who underwent PCI (n = 2,500,796) or CABG (n = 1,496,937) between 1998 and 2001. We calculated the number of patients treated at low volume hospitals and simulated the number of deaths potentially averted by moving all patients to high volume hospitals under best-case conditions (i.e., assuming the full volume-associated reduction in mortality and the capacity to move all patients to high volume hospitals with no related harms).
  
  
  RESULTS
  Multivariate adjusted odds of in-hospital mortality were higher for patients treated in low volume hospitals compared with high volume hospitals for CABG (OR 1.16, 95% CI 1.10-1.24) and PCI (OR 1.12, 95% CI 1.05-1.20). A policy of hospital volume minimums would have required moving 143,687 patients for CABG and 87,661 patients for PCI from low volume to high volume hospitals annually and prevented an estimated 619 CABG deaths and 109 PCI deaths. Thus, preventing a single death would have required moving 232 CABG patients or 805 PCI patients from low volume to high volume hospitals.
  
  
  CONCLUSIONS
  Recommended hospital CABG and PCI volume minimums would prevent 728 deaths annually in the United States, fewer than previously estimated. It is unclear whether a policy requiring the movement of large numbers of patients to avoid relatively few deaths is feasible or effective.
authors.affiliation: Division of Health Policy and Administration, Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut, USA. andrew.epstein@yale.edu
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Epstein
authors.forename: Saif S
authors.initials: SS
authors.lastname: Rathore
authors.forename: Harlan M
authors.initials: HM
authors.lastname: Krumholz
authors.forename: Kevin G M
authors.initials: KG
authors.lastname: Volpp
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000401:mortality* / Q000706:statistics & numerical data*; D001026:Coronary Artery Bypass / Q000401:mortality* / Q000706:statistics & numerical data*; D019992:Databases as Topic; D005260:Female; D017052:Hospital Mortality; D006761:Hospitals / Q000592:standards* / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010351:Patient Discharge; D012017:Referral and Consultation / Q000592:standards*; D012189:Retrospective Studies; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology