Risk factors for early hospital readmission after cardiac operations

Abstract

Objective: Early hospital readmissions after cardiac procedures are both costly and harmful to patients. We investigated the factors that predispose to readmission to develop strategies to minimize this problem. Methods: As part of a prospective data collection, patients having cardiac procedures at our institution are routinely tracked for 30 days after their discharge from the hospital. We reviewed 2650 patients in our cardiac database who underwent operations over the past 5 years. We used univariate and multivariate statistical techniques to identify risks for readmission. Results: Of 2574 discharged patients, 252 (9.8%) required readmission. The most common causes of readmission are cardiac (42%), pulmonary (19%), gastrointestinal (10%), extremity complications (6.7%; deep vein thrombophlebitis, peripheral arterial vascular disease, and saphenous vein harvest site problems), sternal wound problems (7.5%), and metabolic problems (4%). Of more than 70 variables studied, only 6 are significant multivariate predictors of readmission: female sex (P = .002); diabetes (P = .001); chronic lung problems (P = .011); increased distance between home and hospital (P > .001); preoperative atrial fibrillation (P = .002); and preoperative chronic renal insufficiency (P = .002). Type of operation, redo procedures, and other intraoperative and postoperative variables are not important multivariate predictors of readmission. Prolonged hospital length of stay for the initial procedure did not cause more frequent readmission. The costs of initial hospitalization (operating room costs combined with postoperative in-hospital costs) were not significantly increased in those patients who required readmission. Conclusions: The high-risk patient for readmission is a woman with diabetes, chronic lung disease, renal insufficiency, and preoperative atrial fibrillation who lives at a distance from the hospital. Readmission does not depend on periprocedural variables (eg, cardiopulmonary bypass time) or on postoperative complications. High procedural costs from the initial hospitalization do not predispose to readmission. These results suggest interventions that may reduce readmission.