Out-of-Hospital 30-day Deaths After Cardiac Surgery Are Often Underreported

Background: Operative mortality (in-hospital during the index admission or within 30 days of the procedure after discharge) is commonly used as a quality of care measure for public reporting of cardiac surgery outcomes, but the ability to capture out-of-hospital deaths accurately remains undetermined. The objective of the study was to estimate the impact of incomplete reporting of out-of-hospital deaths on hospital risk-adjusted mortality and outlier status. Methods: New York State's 2014 to 2016 cardiac registry data were used to compare the capture of 30-day postprocedure deaths after discharge with and without the use of national and state-level vital statistics data for all 54,442 patients undergoing isolated coronary artery bypass graft, cardiac valve surgery, or both. Hospital risk-adjusted operative mortality rates and mortality outliers were compared based on statistical models that were developed with and without the use of vital statistics data. Results: Thirty-day deaths postprocedure after discharge ranged from 10% to 39% of all operative deaths among cardiac surgical procedures. More than 30% of these deaths were missing without vital statistics confirmation for 7 of the 10 cardiac procedures examined, and more than 40% were missing for 5 of the procedures examined. When vital statistics data were used to confirm 30-day postprocedure deaths after discharge, an additional high outlier for valve surgery was identified. Conclusions: Operative mortality after cardiac surgery is often underreported owing to a considerable percentage of out-of-hospital cardiac surgery deaths that are missed by reporting centers. This can adversely affect the assessment of hospital risk-adjusted mortality in public reports.