Predictors of Long-Term Survival Following Coronary Artery Bypass Grafting Surgery: Results from The Society of Thoracic Surgeons Adult Cardiac Surgery Database (The ASCERT Study)
Background—Most survival prediction models for coronary artery bypass grafting surgery (CABG) are limited to in-hospital or 30-day endpoints. We estimate a long-term survival model using data from the Society of Thoracic Surgeons Adult Cardiac Surgery Database and Centers for Medicare and Medicaid Services (CMS).
Methods and Results—The final study cohort included 348,341 isolated CABG patients ≥ 65 years of age, discharged between January 1, 2002 and December 31, 2007 from 917 STS-participating hospitals, randomly divided into training (n = 174,506) and validation (n = 173,835) samples. Through linkage with CMS claims data, we ascertained vital status from date of surgery through December 31, 2008 (1 - 6 year follow-up). Because the proportional hazards assumption was violated, we fit four Cox regression models conditional on being alive at the beginning of the following intervals: 0 -30 days, 31 - 180 days, 181 days - 2 years, > 2 years. Kaplan-Meier estimated mortality was 3.2% at 30 days, 6.4% at 180 days, 8.1% at one-year, and 23.3% at 3 years of follow-up. Harrell's C statistic for predicting overall survival time was 0.732. Some risk factors (e.g., emergency status, shock, reoperation) were strong predictors of short-term outcome but, for early survivors, became non-significant within 2 years. The adverse impact of some other risk factors (e.g., dialysis-dependent renal failure, insulin-dependent diabetes) continued to increase.
Conclusions—Using clinical registry data and longitudinal claims data, we developed a long-term survival prediction model for isolated CABG. This provides valuable information for shared decision-making, comparative effectiveness research, quality improvement, and provider profiling.
- Received September 8, 2011.
- Accepted January 20, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited