Five-factors Modified Frailty Index role as predictors of outcomes after proximal abdominal aortic aneurysms

Background: The aim of the study was to evaluate the correlation between frailty, measured by the Five-Factor Modified Frailty Index (mFI-5) and mortality and all major adverse events (MAE) in patients who underwent proximal abdominal aortic aneurysm (p-AAA) open surgery (OS). Methods: Data of all elective patients submitted to p-AAA OS from 2010 to 2021 were recorded. Primary endpoints were 30-day mortality and mid-term survival and secondary endpoints included postoperative acute kidney injury (AKI), freedom from aortic reintervention and any MAE. The impact of frailty was assessed by univariate and multivariate analysis; mid-term overall survival were estimated using Kaplan-Meier method (log-rank test). Results: Two-hundred twenty-one patients (197 male, 24 female; aged 72.2±7.4) were included. Thirty-seven (16.4%) were octogenarians (>80 years). The mFI-5 was assessed in the entire group: mean mFI-5 was 0.29±0.12. One-hundred patients (100/221, 45.25%, 91:9 male-to-female ratio) were defined "frail" considering the mFI-5 cut-off >0.25. At univariate analysis a correlation was found between mFI-5>0.25 and mid-term mortality (Pearson correlation [r] 0.280, P<0.001) and AKI (r=0.146, P=0.030). No correlation with 30-day mortality was found (P not significant). At multivariate analysis mFI-5>0.25 increased the risk for midterm mortality (odds ratio 3.32, P=0.021) and postoperative AKI (OR 2.09, P<0.001). The effect of mFI-5>0.25 on mid-term mortality persisted after adjustment for age (P<0.001). Survival was estimated with Kaplan-Meyer method (mean follow-up of 52.7 months, 95% CI: 48.6-56.8); 68 (30.7%) deaths were recorded: 23 among non-frail patients (19.0%) and 45 among frail patients (45/100, 45%, P<0.001). Conclusions: These findings suggest that mFI-5 is a tool capable to identify "frail" patients, who appear to be at increased risk of postoperative AKI and mid-term mortality, but not 30-day mortality. Five-factor modified Frailty Index assessment is simple, fast and can be widely applied in surgical practice to perform appropriate risk stratifications.