Usefulness of platelet-to-lymphocyte ratio as a marker of sarcopenia for critical limb threatening ischemia.

OBJECTIVE 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 ROC curve. Early outcomes of sarcopenic patients in terms of 30-day mortality and 30-day morbidity were retrieved. RESULTS 64 patients were included in the study: 48 non-sarcopenic patients (mean PMI 7.34 cm2/m2; 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 non-sarcopenic 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%). 30-day mortality was 12.5% in the sarcopenic group and 2.1% in the non-sarcopenic group (p=0.15); 30-day morbidity was 56.3% in the sarcopenic group and 10.4% in the non-sarcopenic group (p<0.001). CONCLUSION 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.