Effect of clinical factors on length of stay after coronary artery bypass surgery: Results of the Cooperative Cardiovascular Project

Background Rising health care costs hove prompted careful review of compara tive hospital resource use. Length of stay after bypass surgery has receive d particular attention. However, many providers assert that these variation s are caused by differences in the clinical mix of patients treated, Our go als were to identify the major clinical predictors of postoperative length of slay (PLOS) after coronary artery bypass graft surgery (CABG), document variations in PLOS among 28 hospitals, and assess the degree to which patie nt characteristics account for hospital variations in PLOS. Methods Detailed clinical data on 3605 Medicare patients undergoing CABG in 28 Alabama and lowa hospitals;a were analyzed by stepwise linear regressio n to identify significant clinical predictors of PLOS. Analysis of variance was used to compare hospitals' PLOS while controlling for significant pati ent risk factors. Results The mean age was 72.1 years, 34.7% were female, and the inhospital mortality rate was 5.6%. The median and mean PLOS were 8 and 11.1 days, res pectively. Significant predictors of longer PLOS included increasing age, f emale sex, history of chronic obstructive pulmonary disease, cerebrovascula r disease, or mitral valve disease, elevated admission blood urea nitrogen, and preoperative placement of on intraaortic balloon pump. Hospitals varie d significantly (P = .0001) in their unadjusted PLOS. These hospital-level variations persisted despite adjustment for both preoperative patient chara cteristics (P = .0001) and postoperative complications and death (P = .0001 ). Conclusions This study found significant between-hospital variations in PLO S that were not explained by patient factors. This finding suggests the pot ential for increased efficiency in the care of patients undergoing CABG at many institutions. Further research is needed to determine the practice pat terns contributing to variations in length of stay after bypass surgery.