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Nonclinical factors affect length of hospital stay after coronary artery bypass surgery

Coronary artery bypass graft (CABG) surgery is one of the most common and costly procedures performed in the United States and as such is a major target for cost-containment efforts. Hospitals vary substantially in how long they keep patients in the hospital following CABG surgery. Hospital providers contend that these variations are caused by differences in the clinical mix of patients treated, with hospitals that have longer postoperative length of stay (PLO) saying their patients are sicker. However, a recent study suggests that such clinical factors play only a minor role in explaining variations in hospital PLO for CABG.

In fact, there may be room for increased efficiency and potential cost savings in the care of patients undergoing bypass surgery at certain hospitals, according to the study, which was conducted by the Ischemic Heart Disease Patient Outcomes Research Team (PORT) and supported in part by the Agency for Healthcare Research and Quality (HS06503). Allison B. Rosen, M.P.H., of Duke University Medical Center, and her colleagues analyzed detailed clinical data on 3,605 Medicare patients undergoing CABG surgery in 28 Alabama and Iowa hospitals to identify significant clinical predictors of PLO.

Certain clinical factors predicted longer PLO, such as older age, serious multiple medical conditions, pulmonary disease, and history of congestive heart failure or diabetes. Yet adjustment for case mix of patients treated at each hospital explained only a small amount (4 to 9 percent) of the overall variation in length of stay. Postoperative complications explained an additional 10 percent and death an additional 8 percent of the patient variations in PLO. However, even with these, more than 75 percent of the patient variation in PLO remained unexplained, and hospital variations remained significant (median PLO varied by 4 days and mean PLO by 10 days).

More details are in "Effect of clinical factors on length of stay after coronary artery bypass surgery: Results of the Cooperative Cardiovascular Project," by Dr. Rosen, J. O'Neal Humphries, M.D., Lawrence H. Muhlbaier, Ph.D., and others, in the July 1999 American Heart Journal 138, pp. 69-77.

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