title: Effect of physician volume on the relationship between hospital volume and mortality during primary angioplasty.
abstract: OBJECTIVE
  We sought to examine the combined effect of hospital and physician volume of primary percutaneous coronary intervention (PCI) on in-hospital mortality.
  
  
  BACKGROUND
  An inverse relationship between volume and outcome has been observed for both hospitals and physicians after primary PCI for acute myocardial infarction.
  
  
  METHODS
  Using the New York State PCI registry, we examined yearly hospital volume, physician volume, and risk-adjusted mortality in 7,321 patients undergoing primary PCI for acute myocardial infarction. Risk-adjusted mortality rates for high-volume hospitals (>50 cases/year) and high-volume physicians (>10 cases/year) were compared with their respective low-volume counterparts.
  
  
  RESULTS
  Primary PCI by high-volume hospitals (odds ratio [OR]: 0.58; 95% confidence interval [CI]: 0.38 to 0.88) and high-volume physicians (OR: 0.66; 95% CI: 0.48 to 0.92) was associated with lower odds of mortality. Furthermore, there was a significant interaction between hospital and physician volume on adjusted mortality (p = 0.02). Although unadjusted mortality was lower when primary PCI was performed by high-volume physicians in high-volume hospitals compared with low-volume physicians in low-volume hospitals (3.2% vs. 6.7%, p = 0.03), the risk-adjusted mortality rate was not statistically significant (3.8% vs. 8.4%, p = 0.09). In low-volume hospitals, the average risk-adjusted mortality rate for low-volume physicians was 8.4% versus 4.8% for high-volume physicians (OR: 1.44; 95% CI: 0.68 to 3.03). However, in high-volume hospitals, the risk-adjusted mortality rate for high-volume physicians was 3.8% versus 6.5% for low-volume physicians (OR: 0.58; 95% CI: 0.39 to 0.86).
  
  
  CONCLUSIONS
  During primary PCI, physician experience significantly modifies the hospital volume-outcome relationship. Therefore, policymakers need to consider physician experience when developing strategies to improve access to primary PCI.
authors.affiliation: Department of Medicine, Division of Cardiology, Montefiore Medical Center, Bronx, New York. Electronic address: vsriniva@montefiore.org.
authors.forename: V S
authors.initials: VS
authors.lastname: Srinivas
authors.affiliation: Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Hailpern
authors.affiliation: Department of Medicine, Division of Cardiology, Montefiore Medical Center, Bronx, New York.
authors.forename: Elana
authors.initials: E
authors.lastname: Koss
authors.affiliation: Department of Medicine, Division of Cardiology, Montefiore Medical Center, Bronx, New York.
authors.forename: E Scott
authors.initials: ES
authors.lastname: Monrad
authors.affiliation: Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Alderman
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000401:mortality* / Q000706:statistics & numerical data; D002983:Clinical Competence; D005260:Female; D017052:Hospital Mortality; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality* / Q000628:therapy; D010820:Physicians / Q000706:statistics & numerical data*; D016896:Treatment Outcome