Background: End-stage kidney disease (ESKD) is commonly associated with critical limb-threatening ischemia (CLTI) and frailty. Yet there are no specific tools to predict outcomes of CLTI in ESKD, particularly those that incorporate frailty. We aimed to assess the utility of the medical record-based Hospital Frailty Risk (HFR) score in predicting outcomes of CLTI in ESKD. Methods and Results: We identified patients with ESKD diagnosed with CLTI from the US Renal Data System from 2015 to 2018. These patients were categorized into 3 frailty risk groups on the basis of their HFR scores: low (<5), intermediate (5-10), high-risk (>10), and on the basis of whether they underwent revascularization (endovascular revascularization [ER]/surgical revascularization [SR]) or not (no revascularization). Primary outcomes of interest included in-hospital composite of death or major amputation and in-hospital death. We included 49 454 eligible patients, with ER/SR cohort including 19.8% (n=9777). A total of 88.4% (ER/SR) and 90.0% (no revascularization) were frail on the HFR scale. We found a nonlinear association between HFR score and in-hospital adverse outcomes. In both cohorts, intermediate and high-risk HFR scores were associated with greater risk of in-hospital death (high-risk, ER/SR: odds ratio, 2.7 [95% CI, 1.6-4.8]; P<0.0001; no revascularization: odds ratio, 7.8 [95% CI, 5.3-11.6]; P<0.01) and composite of in-hospital major amputation or death (high-risk, ER/SR: odds ratio, 2.4 [95% CI, 1.9-3.1]; P<0.0001; no revascularization: odds ratio, 1.7 [95% CI, 1.5-1.9]; P<0.0001). Conclusions: The HFR score can predict risk of in-hospital death and composite of death or major amputation in patients with ESKD and CLTI. Further data are needed to determine the utility of the HFR score in this population.
