To compare the predictive ability of the modified Frailty Index (mFI) and the revised Risk Analysis Index (RAI-Rev) for perioperative outcomes in patients undergoing major urologic oncologic surgery, aiming to identify the optimal frailty screening tool for surgical risk stratification.

NSQIP was queried to identify patients undergoing radical prostatectomy, partial or radical nephrectomy, or radical cystectomy between 2013 and 2017. We investigated the association of mFI and RAI-Rev with the following 30-day perioperative outcomes using multivariable logistic regression: major complications, Clavien grade ≥4 complications, non-home discharge, 30-day readmission, and all-cause mortality. Receiver-operating characteristic curve analysis compared the predictive performances of the 2 frailty instruments, with differences between the C-statistics assessed using DeLong's test.

Among 101,739 patients, 30-day major complication rates varied from 2.40% in prostatectomy to 26.86% in cystectomy, non-home discharge rates ranged from 1.92% to 13.54%, and mortality rates were between 0.16% and 1.43%. RAI-Rev showed higher discriminatory ability for mortality (C-statistic: 0.688-0.798) and non-home discharge (C-statistic: 0.638-0.734) compared to mFI (C-statistic: 0.594-0.677 and 0.593-0.639, respectively). Both frailty indices had similar discriminatory ability for major perioperative complications (C-statistic: 0.531-0.607). DeLong's test confirmed statistically significant differences in C-statistics between RAI-Rev and mFI for mortality (P <.001) and non-home discharge (P <.001) across all surgical cohorts.

RAI-Rev may have greater utility as a frailty prognostic tool than mFI among patients undergoing major urologic surgery. Prospective studies and clinical trials exploring frailty should consider these results during trial design.