Associations of clinical frailty with severity of limb threat and outcomes in chronic limb-threatening ischaemia

Abstract

Objective: Investigate the relationship of frailty and severity of chronic limb-threatening ischaemia (CLTI), and their comparative associations with one-year outcomes, in patients presenting to a vascular limb salvage (VaLS) clinic. Methods: This retrospective cohort study utilised data collected from a prospectively maintained VaLS clinic database. Patients aged ≥50 presenting to the VaLS clinic with CLTI between February 2018 and April 2019 were included. Frailty was measured using the Clinical Frailty Scale (CFS) and limb threat severity by the Wound, Ischaemia, and foot Infection (WIfI) score. Excessive polypharmacy was defined as ≥10 medications. Anticholinergic burden (ACB) score and Charlson comorbidity index (CCI) were calculated for all patients. The primary outcome measure was a composite endpoint of death or amputation at one-year. Associations with outcome were assessed using Cox regression and reported as hazards ratios (HR) with 95% confidence intervals (CI). Results: A total of 198 patients were included, with CFS scores available for 190 patients. 98 patients (52%) were frail (CFS ≥5). 127 patients (67%) initially underwent endovascular revascularisation. Excessive polypharmacy was common (55 patients; 28%). Frailty was associated with increased WIfI stage (P = 0.025) as well as age, female sex, CCI score, number of medications, excessive polypharmacy but not ACB score. Frail patients were more frequently managed non-operatively (P = 0.017). Frailty (HR 1.91; 95% CI 1.09, 3.34; P = 0.024) and WIfI stage 4 (HR 3.29; 95%CI 1.23, 8.80; P = 0.018) were associated with death or amputation on univariable analysis. WIfI stage 4 (HR 2.80; 95%CI 1.04, 7.57; P = 0.042) and CCI score (HR 1.21; 95%CI 1.03, 1.41; P = 0.015), but not frailty (HR 1.25; 95%CI 0.67, 2.33; P = 0.474), were independently associated with death or amputation on multivariable analysis. Conclusions: Frailty is highly prevalent among CLTI patients and related to severity of limb threat. The CFS may be a useful adjunct to patient risk assessment in CLTI.