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[Quality assessment indicators of cardiac surgeons' work; the validity of mortality rates]
E Dekker1, H A Verheul, R B van den Brink
1Vakgroep Cardiologie, Academisch Medisch Centrum/Universiteit van Amsterdam.
Insights
Comparing heart surgeon mortality rates requires careful risk adjustment. Initial analysis showed higher mortality for one surgeon, but this difference disappeared after accounting for patient risk profiles, indicating no quality disparity.
Area of Science:
- Cardiovascular Surgery
- Outcomes Research
- Health Services Research
Context:
- Assessing surgeon performance is crucial for quality improvement in cardiac surgery.
- Variations in patient risk profiles can confound direct comparisons of surgical outcomes.
- Cardiac valve replacement is a common procedure with significant implications for patient survival.
Purpose:
- To investigate whether observed differences in mortality rates between cardiac surgeons reflect true quality variations or patient-related factors.
- To evaluate the necessity of risk adjustment when comparing surgeon-specific outcomes in cardiac valve replacement.
Summary:
- A retrospective cohort study of 783 cardiac valve replacement patients (446 aortic, 337 mitral) was conducted.
- Initial analysis revealed a higher one-year mortality rate (16.4%) for patients operated by surgeon A compared to peers (9.5%).
- After multivariate correction for differing patient risk profiles, the statistically significant difference in mortality between surgeon A and other surgeons vanished.
Impact:
- Demonstrates that unadjusted mortality rates can be misleading when comparing surgeon performance.
- Highlights the critical importance of thorough risk adjustment in evaluating the quality of care in complex surgical procedures.
- Emphasizes that patient selection and risk stratification are key factors in interpreting surgical outcomes data.
Objective:
To determine the possibility of comparing the mortality rates of patients operated by different heart surgeons with each other.
Design:
Retrospective cohort study.
Setting:
Academic Medical Centre, Amsterdam, the Netherlands.
Patients And Methods:
Clinical information, operation data and follow-up data on 783 patients who had undergone cardiac valve replacement, were collected from the clinical records. Aortic valve replacement had been performed in 446 patients (1979-1986) and mitral valve replacement in 337 patients (1980-1990).
Results:
The one-year mortality rate was higher among patients operated on by heart surgeon A than among patients operated on by the other heart surgeons from the same team, viz. 16.4% and 9.5%, respectively, an absolute difference of 6.9%. The 95% confidence interval of the difference was 1.7-12.9. However, it was also found that the risk profiles of these patients of surgeon A differed from those of the other patients. After multivariate correction for this difference in risk profile, the difference in mortality was no longer statistically significant.
Conclusion:
The differences in mortality observed in our study could not be attributed to difference in quality of the heart surgeons, but were related with the risk profiles of the patients operated by one of them. Thorough analysis with correction for risks is necessary for the assessment of the quality of care, if the conclusions are not to be misleading.