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Published on: August 9, 2024
Differences Among Cardiologists in Rates of Positive Coronary Angiograms
Jason H Wasfy1, Michael K Hidrue2, Robert W Yeh3
1Massachusetts 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.).
Insights
Variation in positive coronary angiograms among cardiologists is minimal after accounting for patient factors. This highlights the need for risk adjustment in healthcare quality and value reporting.
Area of Science:
- Cardiovascular Medicine
- Health Services Research
- Medical Quality Improvement
Background:
- High-cost services like coronary angiography have variable diagnostic yields nationally, suggesting potential overutilization.
- Understanding variation in cardiologist referral patterns for cardiac catheterization is key to improving healthcare quality and value.
- This study aimed to analyze and explain variations in positive coronary angiogram results among referring cardiologists.
Purpose of the Study:
- To assess and explain the variation in positive diagnostic coronary angiograms among referring cardiologists.
- To determine if physician-level differences, beyond patient clinical factors, contribute significantly to angiogram positivity rates.
Main Methods:
- Retrospective analysis of diagnostic coronary angiograms performed at Massachusetts General Hospital (Jan 2012-June 2013).
- Exclusion of angiograms for acute coronary syndrome and those from cardiologists with fewer than 10 referrals.
- Mixed-effects logistic regression models were used to identify predictors of positive angiograms (≥50% stenosis) and assess physician-level variation using median odds ratios.
Main Results:
- Of 2925 eligible angiograms, 49.6% were positive. Significant predictors included patient age, male sex, and peripheral arterial disease.
- After adjusting for clinical variables, the median odds ratio for variation between physicians was 1.23, indicating only borderline clinical significance.
- In the full model including clinical and non-clinical factors, the median odds ratio was 1.07, suggesting clinically insignificant variation attributable to the referring cardiologist.
Conclusions:
- While some variation exists among cardiologists in ordering coronary angiograms, it is largely explained by patient clinical factors.
- The observed variation in positive angiogram rates among physicians was borderline to clinically insignificant after risk adjustment.
- These findings underscore the critical importance of robust risk adjustment when reporting on quality and value metrics in cardiology.
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.
Methods And 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.
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