title: Differences Among Cardiologists in Rates of Positive Coronary Angiograms.
abstract: BACKGROUND
  Understanding the sources of variation for high-cost services has the potential to improve both patient outcomes and value in health care delivery. Nationally, the overall diagnostic yield of coronary angiography is relatively low, suggesting overutilization. Understanding how individual cardiologists request catheterization may suggest opportunities for improving quality and value. We aimed to assess and explain variation in positive angiograms among referring cardiologists.
  
  
  RESULTS
  We identified all cases of diagnostic coronary angiography at Massachusetts General Hospital from January 1, 2012, to June 30, 2013. We excluded angiograms for acute coronary syndrome. For each angiogram, we identified clinical features of the patients and characteristics of the requesting cardiologists. We also identified angiogram positivity, defined as at least 1 epicardial coronary stenosis ≥50% luminal narrowing. We then constructed a series of mixed-effects logistic regression models to analyze predictors of positive coronary angiograms. We assessed variation by physician in the models with median odds ratios. Over this time period, 5015 angiograms were identified. We excluded angiograms ordered by cardiologists requesting <10 angiograms. Among the remaining 2925 angiograms, 1450 (49.6%) were positive. Significant predictors of positive angiograms included age, male patients, and peripheral arterial disease. After adjustment for clinical variables only, the median odds ratio was 1.23 (95% CI 1.0-1.36), consistent with only borderline clinical variation after adjustment. In the full clinical and nonclinical model, the median odds ratio was 1.07 (95% CI 1.07-1.20), also consistent with clinically insignificant variation.
  
  
  CONCLUSIONS
  Substantial variation exists among requesting cardiologists with respect to positive and negative coronary angiograms. After adjustment for clinical variables, there was only borderline clinically significant variation. These results emphasize the importance of risk adjustment in reporting related to quality and value.
authors.affiliation: Massachusetts General Physicians Organization, Harvard Medical School, Boston, MA (J.H.W., M.K.H., T.G.F.) Cardiology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA (J.H.W., R.W.Y., W.D., E.V.P., M.A.F.).
authors.forename: Jason H
authors.initials: JH
authors.lastname: Wasfy
authors.affiliation: Massachusetts General Physicians Organization, Harvard Medical School, Boston, MA (J.H.W., M.K.H., T.G.F.).
authors.forename: Michael K
authors.initials: MK
authors.lastname: Hidrue
authors.affiliation: Cardiology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA (J.H.W., R.W.Y., W.D., E.V.P., M.A.F.).
authors.forename: Robert W
authors.initials: RW
authors.lastname: Yeh
authors.affiliation: Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA (K.A., T.G.F.).
authors.forename: Katrina
authors.initials: K
authors.lastname: Armstrong
authors.affiliation: Cardiology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA (J.H.W., R.W.Y., W.D., E.V.P., M.A.F.).
authors.forename: G William
authors.initials: GW
authors.lastname: Dec
authors.affiliation: Cardiology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA (J.H.W., R.W.Y., W.D., E.V.P., M.A.F.).
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Pomerantsev
authors.affiliation: Cardiology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA (J.H.W., R.W.Y., W.D., E.V.P., M.A.F.).
authors.forename: Michael A
authors.initials: MA
authors.lastname: Fifer
authors.affiliation: Massachusetts General Physicians Organization, Harvard Medical School, Boston, MA (J.H.W., M.K.H., T.G.F.) Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA (K.A., T.G.F.) Partners Healthcare, Boston, MA (T.G.F.).
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Ferris
mesh_terms: D001900:Boston; D017023:Coronary Angiography / Q000639:trends*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006769:Hospitals, General; D006801:Humans; D016015:Logistic Models; D008297:Male; D015588:Observer Variation; D016017:Odds Ratio; D010818:Practice Patterns, Physicians' / Q000639:trends*; D011237:Predictive Value of Tests; D012017:Referral and Consultation / Q000639:trends*; D015203:Reproducibility of Results; D012307:Risk Factors
keywords: coronary angiography; outcomes research; variation analysis