Frailty Assessment and the Risk of Major Adverse Cardiac Events after Elective Surgery

BACKGROUND: Frailty may increase the risk of major adverse cardiovascular events (MACE) after non-cardiac surgery. We aimed to assess the association between frailty and MACE after non-cardiac surgery and potential improvements in the performance of the Revised Cardiac Risk Index (RCRI) with the addition of frailty status. METHODS: We conducted a retrospective cohort study of older US adults aged ≥65 insured through Medicare undergoing non-cardiac surgery between 1/2015 and 9/2021. Frailty was assessed with the Hospital Frailty Risk Score, categorized as low(<5), intermediate(5-14), and high(≥15). The primary outcome was 30-day major adverse cardiovascular events (MACE; mortality, myocardial infarction, stroke, or heart failure). Patients with intermediate/high frailty were propensity-matched 1:1 with low-frailty patients with exact match on age, sex, race, surgical procedure, and RCRI. The incremental utility of adding categorical frailty to RCRI was assessed by comparing concordance statistics and receiver-operating characteristics. RESULTS: Among 6,399,535 patients (mean age 73y, 43% male), 22.4% had intermediate/high frailty, and 2.97% experienced 30-day MACE. In the propensity-matched cohort, frailty was associated with higher odds of 30-day MACE (OR[95%CI]: 1.19[1.17-1.21], P<0.001) and mortality (OR[95%CI]: 1.53[1.49-1.58], P<0.001). The association of frailty with MACE was stronger in patients with low baseline cardiac risk (RCRI 0-1: OR[95%CI] 1.28[1.25-1.31]) versus high risk (RCRI 2-4: OR[95% CI]:1.06[1.03-1.09]; Pinteraction<0.001). Adding frailty to RCRI improved predictive performance for 30-day MACE (C-index: 0.773 vs. 0.758, P<0.001; Brier score: 0.0277 vs. 0.0290). CONCLUSION: Frailty before non-cardiac surgery was associated with increased 30-day MACE. Incorporating frailty into RCRI improves risk prediction, particularly for patients with low baseline cardiac risk.