Improving coronary artery bypass grafting readmission outcomes from 2000 to 2012 in the Medicare population.

Objective: The study objective was to examine trends in 30-day readmission after coronary artery bypass grafting in the Medicare population over 13 years. Methods: The study included isolated coronary artery bypass grafting procedures in the Medicare population from January 2000 to November 2012. Comorbidities and causes of readmission were determined using Internal Classification of Diseases, 9th Revision, Clinical Modification diagnostic codes. Results: The cohort included 1,116,991 patients. Readmission rates decreased from 19.5% in 2000 to 16.6% in 2012 (P=.0001). There was significant improvement across all categories of admission status, age, race, gender, and hospital annual coronary artery bypass grafting volume that were analyzed. Adjusted odds of readmission in 2000 compared with 2012 was 1.28 (95% confidence interval, 1.24-1.32). Median length of stay for the readmission episode was 5 days, which improved to 4 days by 2012. Hospital mortality during the readmission episode was 2.8% overall and declined to 2.4% in 2012 (P=.0001). The most common primary readmission diagnoses were heart failure (12.6%), postoperative wound infection/nonhealing wound (8.9%), arrhythmias (6.4%), and pleural effusions (3.7%). Readmission for wound infections/nonhealing wounds decreased significantly over time, from 9.8% to 6.5% (P=.0001). Conclusions: In a large cohort of Medicare patients undergoing coronary artery bypass grafting over 13 years, there was a significant decrease in 30-day readmission rates, a reduction in readmission for wound infections, and reduced mortality during the readmission episode, despite an increase in patient comorbidities. The improvement in readmission rates was seen regardless of patient variables examined.