Usefulness of Platelet-to-Lymphocyte Ratio as a Marker of Sarcopenia for Critical Limb Threatening Ischemia

Abstract

Sarcopenia is a factor of poor prognosis for patients with critical limb threatening ischemia (CLTI), but its diagnosis requires imaging measurements and is time consuming. We investigated whether preoperative platelet-to-lymphocyte ratio (PLR) could be an easy and rapid marker of sarcopenia. Patients treated for CLTI between January 2019 and July 2019 were included in this single-center retrospective study. Sarcopenia was defined by a psoas muscle index (PMI) <5.5cm2/m2 in men, and <4.0cm2/m2 in women. PLR was calculated for all patients based on their systematic preoperative blood analysis. The diagnostic power of PLR was analyzed through a receiver operating characteristic (ROC) curve. Early outcomes of sarcopenic patients in terms of 30-day mortality and 30-day morbidity were retrieved. Sixty-four patients were included in the study: 48 nonsarcopenic patients (mean PMI 7.34cm2/m2; interquartile range [IQR] 6.58-8.01) and 16 sarcopenic patients (mean PMI 4.30cm2/m2; IQR 3.45-5.17). No difference was found between both groups regarding patient demographics, clinical characteristics, cardiovascular risk factors, comorbidities, or revascularization modalities. PLR was significantly higher in the sarcopenic group (mean 332.1; IQR 158.2-320.7) compared with the nonsarcopenic group (mean 204.6; IQR 133.8-265.6) (P=0.02). A PLR value ≥292.5 was shown to be a diagnostic marker for sarcopenia based on the ROC curve (sensitivity 31.3%, specificity 91.7%). Thirty-day mortality was 12.5% in the sarcopenic group and 2.1% in the nonsarcopenic group (P=0.15); 30-day morbidity was 56.3% in the sarcopenic group and 10.4% in the nonsarcopenic group (P<0.001). PLR might help identifying a subgroup of CTLI patients associated with poor prognosis but does not seem appropriate to be used as a marker of sarcopenia given its low sensitivity.