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

Background: Impaired exercise tolerance during formal testing is predictive of perioperative complications. However, for most patients, formal exercis e testing is not indicated, and exercise tolerance is assessed by history. Objective: To determine the relationship between self-reported exercise tol erance and serious perioperative complications. Methods: Our study group consisted of 600 consecutive outpatients referred to a medical consultation clinic at a tertiary care medical center for preo perative evaluation before undergoing 612 major noncardiac procedures. Pati ents were asked to estimate the number of blocks they could walk and Rights of stairs they could climb without experiencing symptomatic limitation. Pa tients who could not walk 4 blocks and climb 2 flights of stairs were consi dered to have poor exercise tolerance. All patients were evaluated for the development of 26 serious complications that occurred during hospitalizatio n. Results: Patients reporting poor exercise tolerance had more perioperative complications (20.4% vs 10.4%; P < .001). Specifically, they had more myoca rdial ischemia (P = .02) and more cardiovascular (P = .04) and neurologic ( P = .03) events. Poor exercise tolerance predicted risk for serious complic ations independent of all other patient characteristics, including age (adj usted odds ratio, 1.94; 95% confidence interval, 1.19-3.17). The likelihood of a serious complication occurring was inversely related to the number bl ocks that could be walked (P = .006) or flights of stairs that could be cli mbed (P = .01). Other patient characteristics predicting serious complicati ons in multivariable regression analysis included history of congestive hea rt failure, dementia, Parkinson disease, and smoking greater than or equal to 20 pack-years. Conclusion: Self-reported exercise tolerance can be used to predict in-hosp ital perioperative risk, even when using relatively simple and familiar mea sures.