SAN FRANCISCO – Awareness of four factors that predict increased risk for hospital readmission after coronary artery bypass grafting may improve physicians’ ability to reduce early readmission rates among patients undergoing the procedure.
The four factors that independently predicted increased risk for hospital readmission after CABG in a study of 818 patients were preoperative congestive heart failure, chronic lung disease, a body mass index of 40 kg/m2 or greater, and longer time spent on cardiopulmonary bypass, Dr. Kelly B. Currie said at the annual clinical congress of the American College of Surgeons.
Medicare payments to hospitals with high readmission rates will be reduced starting in October 2012 under provisions of the Patient Protection and Affordable Care Act. Payments will change from a fee-for-service model to a value-based model.
Readmission rates within 30 days of CABG range from 6% to 21% in the medical literature. In the third quarter of 2010, 10% of patients in the Society of Thoracic Surgeons (STS) database who underwent CABG were readmitted within 30 days, said Dr. Currie, a surgery resident at Bassett Medical Center, Cooperstown, N.Y.
She and her associates analyzed data from 460 patients undergoing CABG at their center from 2003 to 2010 and from 358 patients in the STS Heartsource database. Once they identified independent predictors of readmission, they conducted a second logistic regression analysis on the 358 patients in the STS database and created a "probability calculator" of readmission risk.
Congestive heart failure was associated with a 77% increase in risk for early readmission after CABG, and chronic lung disease was associated with an 82% increase in risk. The risk of readmission increased significantly by 0.6% with longer perfusion time, and increased nearly fourfold in obese patients with a body mass index of 40 or greater compared with normal-weight patients.
The risk for readmission decreased significantly by 40% in patients who underwent endoscopic vein harvest, she added.
Physicians may want to focus resources on the high-risk patients to decrease readmissions, Dr. Curry said. Readmissions might be lessened by instituting follow-up calls within a day of discharge, and/or having patients see their primary care physicians within 7 days of discharge. Efforts to improve verbal handoffs of patient care between inpatient nurses and visiting nurses, as well as the use of telemedicine, might be other effective ways to help avoid readmissions, she suggested.
"These are things we are going to be implementing in the near future, hopefully," she said.
The readmission risk calculator developed in this study probably cannot be applied to a broad population of patients because some of the variables are specific to the cardiac surgery population, she noted. The study’s techniques could be applied, however, to develop risk calculators for other populations.
Dr. Currie is collaborating with researchers at Columbia University in New York to develop an improved calculator by studying data on an expected 1,400 adult cardiac surgery cases at nine hospitals in five states.
Dr. Currie said she has no relevant conflicts of interest.