Preoperative frailty and adverse outcomes following coronary artery bypass grafting surgery in US veterans

Abstract Background Contemporary guidelines emphasize the value of incorporating frailty into clinical decision‐making regarding revascularization strategies for coronary artery disease. Yet, there are limited data describing the association between frailty and longer‐term mortality among coronary artery bypass grafting (CABG) patients. Methods We conducted a retrospective cohort study (2016–2020, 40 VA medical centers) of US veterans nationwide that underwent coronary artery bypass grafting (CABG). Frailty was quantified by the Veterans Administration Frailty Index (VA‐FI), which applies the cumulative deficit method to render a proportion of 30 pertinent diagnosis codes. Patients were classified as non‐frail (VA‐FI ≤ 0.1), pre‐frail (0.1 < VA‐FI ≤ 0.2), or frail (VA‐FI > 0.2). We used Cox proportional hazards models to ascertain the association of frailty with all‐cause mortality. Our primary study outcome was 5‐year all‐cause mortality; the co‐primary outcome was days alive and out of the hospital within the first postoperative year. Results There were 13,554 CABG patients (median 69 years, 79% White, 1.5% women). The mean pre‐operative VA‐FI was 0.21 (SD: 0.11); 31% were pre‐frail (VA‐FI: 0.17) and 47% were frail (VA‐FI: 0.31). Frail patients were older and had higher co‐morbidity burdens than pre‐frail and non‐frail patients. Compared with non‐frail patients (13.0% [11.4, 14.7]), there was a significant association between frail and pre‐frail patients and increased cumulative 5‐year all‐cause mortality (frail: 24.8% [23.3, 26.1]; HR: 1.75 [95% CI 1.54, 2.00]; pre‐frail 16.8% [95% CI 15.3, 18.4]; HR 1.2 [1.08,1.34]). Compared with non‐frail patients (mean 362[SD 12]), pre‐frail (mean 361 [SD 14]; p < 0.01) and frail patients (mean 358[SD 18]; p < 0.01) spent fewer days alive and out of the hospital in the first postoperative year. Conclusions Pre‐frailty and frailty were prevalent among US veterans undergoing CABG and associated with worse mid‐term outcomes. Given the high prevalence of frailty with attendant adverse outcomes, there may be an opportunity to improve outcomes by identifying and mitigating frailty before surgery.