Self-reported exercise tolerance and the risk of serious perioperative complications

Impaired exercise tolerance during formal testing is predictive of perioperative complications. However, for most patients, formal exercise testing is not indicated, and exercise tolerance is assessed by history.

To determine the relationship between self-reported exercise tolerance and serious perioperative complications.

Our study group consisted of 600 consecutive outpatients referred to a medical consultation clinic at a tertiary care medical center for preoperative evaluation before undergoing 612 major noncardiac procedures. Patients were asked to estimate the number of blocks they could walk and flights of stairs they could climb without experiencing symptomatic limitation. Patients who could not walk 4 blocks and climb 2 flights of stairs were considered to have poor exercise tolerance. All patients were evaluated for the development of 26 serious complications that occurred during hospitalization.

Patients reporting poor exercise tolerance had more perioperative complications (20.4% vs 10.4%; P<.001). Specifically, they had more myocardial ischemia (P = .02) and more cardiovascular (P = .04) and neurologic (P = .03) events. Poor exercise tolerance predicted risk for serious complications independent of all other patient characteristics, including age (adjusted odds ratio, 1.94; 95% confidence interval, 1.19-3.17). The likelihood of a serious complication occurring was inversely related to the number blocks that could be walked (P = .006) or flights of stairs that could be climbed (P = .01). Other patient characteristics predicting serious complications in multivariable regression analysis included history of congestive heart failure, dementia, Parkinson disease, and smoking greater than or equal to 20 pack-years.

Self-reported exercise tolerance can be used to predict in-hospital perioperative risk, even when using relatively simple and familiar measures.