Cardiovascular Outcomes Research Laboratories (CORELAB), University of California Los Angeles, Los Angeles, California; Division of Cardiac Surgery, University of California Los Angeles, Los Angeles, California. Electronic address: [Email]
Readmission following cardiac surgery is associated with poor outcomes and increased healthcare expenditure. However, a nationwide understanding of the incidence, cost, causes, and predictors of 30-day readmission following coronary artery bypass grafting is limited. The Nationwide Readmissions Database was used to identify all adult patients who underwent isolated coronary artery bypass grafting (CABG) with no other concomitant surgery between 2010 and 2014. The primary outcome was all-cause readmission within 30 days of discharge after surgery. Risk-adjusted multivariable analyses were used to develop a model of readmission risk. Of 855,836 patients, 95,504 (11.2%) had an emergent 30-day readmission following CABG. The most common causes of readmission were related to respiratory complications (17.1%), infection (13.5%), and heart failure (11.9%). Readmission cost an average of $13,392 per patient, accounting for an estimated annual cost of over $250 million. Independent predictors of 30-day readmission encompassed female gender (odds ratio [OR] 1.27; 95% confidence interval [CI] 1.24 to 1.31), emergent index admission (OR 1.29; 95% CI 1.25 to 1.33), and preoperative co-morbidities, including atrial fibrillation (OR 1.24; 95% CI 1.21 to 1.28), liver disease (OR 1.29; 95% CI 1.17 to 1.41), renal failure (OR 1.38; 95% CI 1.34 to 1.43), among others. CABG performed at a high CABG volume hospital was protective of readmission (OR 0.95; 95% CI 0.91 to 0.99). In conclusion, we characterized using a national sample the incidence, causes, costs, and predictors of 30-day readmission following CABG. Targeting modifiable risk factors for readmission should be a priority to reduce rates of readmission and decrease healthcare expenditure.