Comparison of Cardiac Surgery Volumes and Mortality Rates Between The Society of Thoracic Surgeons and Medicare Databases From 1993 Through 2001

Background: This study compares surgical volumes and mortality rates in the Society of Thoracic Surgeons voluntary clinical National Cardiac Database (NCD) with those from an administrative claims database (Medicare Provider Analysis and Review [MedPAR]) to assess the suitability of the NCD for tracking national cardiac surgery outcomes. Methods: Hospitals common to both databases were matched. In each database, patients aged 65 years and older who underwent coronary artery bypass grafting, aortic valve replacement, and mitral valve replacement in United States hospitals from 1993 to 2001 were identified. Results: Annual volumes for all procedures were consistently higher in the NCD. This may be attributed to Medicare managed care; a Medicare group not collected into MedPAR. In-hospital mortality rates trended lower over time and were comparable between the databases. Surgical volumes were generally higher and mortality rates lower for hospitals that submitted data to the NCD than for those that did not. Conclusions: The close match between NCD and MedPAR in-hospital mortality rates combined with the larger volumes in the NCD suggest that under-reporting in the NCD is not a significant issue. Further investigations into the accuracy of both the NCD and MedPAR are necessary because both are being used for evaluation of provider quality.