Elevated Risk Analysis Index (RAI) Frailty Scores Are Independently Associated with Adverse Outcomes in Lower Extremity Surgical Revascularizations Similarly Across Genders

Abstract

The Risk Analysis Index (RAI) frailty scoring system has recently undergone revision and external validation using the National Surgical Quality Improvement Program (NSQIP) database. We set forth to evaluate the association of RAI-rev ranges with outcomes following lower extremity surgical revascularization and verify equivalent applicability across genders. All elective NSQIP Targeted Lower Extremity Open cases from 2015-2019 were divided by EMR-recorded gender. Aggregate demographics, perioperative factors, and 30-day outcomes were compared using unpaired t-test and Fisher's exact test. Adjusted odds-ratios (aOR) for each outcome were generated by applying a multivariate binary logistic regression model (IBM SPSSTM) for five-point RAI-rev score increments from 25-45 and a most-frail group with scores >45 with a non-frail reference of <25. Covariates included surgical indication, prior ipsilateral revascularization, graft utilization, dirty/infected wound, smoking, hypertension, diabetes, and steroid use. 8,155 cases included 2,498 (31%) performed in women who demonstrated slightly lower RAI-rev scores than men (22.1 ± 5.8 vs. 24.2 ± 5.1; P = 0.0001). Univariate trends demonstrated dose-dependent increases in frequency of most outcomes with rising frailty score ranges, most substantially regarding mortality (0.4% non-frail to 14.7% most-frail), disposition to skilled nursing facility (8% non-frail to 27% most-frail), and extended length of stay (16% non-frail to 44% most-frail). After adjusting for co-variates, patients with RAI-rev scores of 26-30 had aOR of 1.4 (95% CI: 1.2-1.6; P < 0.001), 1.9 (95% CI: 1.6-2.2; P < 0.001), and 2.4 (95% CI:1.3-4.4; P < 0.001) for extended stay, disposition to skilled nursing, and mortality respectively. Trends were similar across genders in both univariate and multivariate analyses. Mortality, extended stay, and increased rehabilitation needs after surgical revascularization were associated with higher RAI-rev score ranges in a dose dependent manner similarly across genders.