Following institutional research ethics approval from the University Health Network, Toronto, Ontario, Canada, we obtained written informed consent from patients who were 40 years or older, scheduled to undergo major elective noncardiac surgery at the Toronto General Hospital, Toronto, and had 1 or more risk factors (ie, coronary artery disease, heart failure, cerebrovascular disease, diabetes, hypertension, peripheral arterial disease, age ≥70 years, renal insufficiency, smoking). Participants completed the DASI questionnaire at their preoperative assessment clinic visit. DASI scores were divided by 3.5 to estimate METS.5 The attending anesthesiologist in the clinic or operating room, while blinded to DASI scores, rated each participant’s functional capacity as “unfit” (<4 METs), “normal” (4-10 METs), or “fit” (>10 METs) based on their usual preoperative examination, which typically assessed activities of daily living and exercise capacity (eg, ability to climb stairs). Each participant was evaluated by any one of 38 consultant anesthesiologists. A sample size of 74 was required to measure a Pearson correlation coefficient of 0.60, with a lower 2-sided 95% confidence limit excluding 0.30 with 90% power.