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

Background: 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. Methods: 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) <5.5 cm²/m² in men, and <4.0 cm²/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. Results: Sixty-four patients were included in the study: 48 nonsarcopenic patients (mean PMI 7.34 cm²/m²; interquartile range [IQR] 6.58–8.01) and 16 sarcopenic patients (mean PMI 4.30 cm²/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). Conclusions: 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.