Evaluation of three nutritional indices as predictors of 2-year mortality and major amputation in patients with chronic limb-threatening ischemia

Objective: The present study aimed to examine which nutritional index, such as the controlling nutritional status (CONUT), prognostic nutritional index (PNI), and geriatric nutritional risk index (GNRI), is better for predicting prognosis in patients with chronic limb-threatening ischemia (CLTI) following revascularization. Method: We retrospectively analyzed data of patients who underwent revascularization for CLTI between 2008 and 2020. The endpoints were 2-year overall survival and limb salvage. The optimal cutoff values of 2-year overall survival and major amputation were determined by receiver operating characteristic curve analyses. Result: A total of 238 patients with CLTI and 289 limbs were analyzed. The 2-year overall survival rates were 48.9%, 54.6%, and 53.5% in patients with CONUT score ≥4, PNI score <42.6, and GNRI <98.4 compared with 80.0%, 80.0%, and 78.4% in patients with CONUT score <4, PNI score ≥42.6, and GNRI ≥98.4 (p < 0.01). Age, non-ambulatory status, hemodialysis, and nutritional indices were independent risk factors for 2-year mortality in the multivariate analyses. The 2-year limb salvage rates were 70.1%, 82.2%, and 81.9% in patients with CONUT score ≥7, PNI score <41.9, and GNRI <95.3 compared with 92.8%, 98.3%, and 94.2% in patients with CONUT score <7, PNI score ≥41.9, and GNRI ≥95.3 (p < 0.01). Wound, ischemia, and foot infection stage and each nutritional index (CONUT and PNI) were independent risk factors for major amputation in multivariate analyses. The overall survival and limb salvage rates of patients with malnutrition diagnosed by CONUT score were poor compared with those of normal nutrition or malnutrition diagnosed by PNI and/or GNRI scores. Conclusion: The CONUT, PNI, and GNRI scores can predict the 2-year overall survival in patients with CLTI after revascularization. The CONUT and PNI scores were associated with major amputation.