Association of Baseline Neutrophil to Lymphocyte and Platelet to Lymphocyte Ratios with Relapse in Sarcoidosis: A Single Center Retrospective Study

Background: Sarcoidosis is a heterogeneous multisystem granulomatous disease characterized by variable clinical course and relapse potential. Current ATS, BTS, and ERS guidance highlights the need for accessible biomarkers that may support clinical assessment and longitudinal follow up. Inflammatory hematologic indices such as neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) have been investigated as potential markers of disease activity in sarcoidosis. This study aimed to evaluate the association of baseline NLR and PLR values with clinical phenotype and relapse in sarcoidosis patients.Methods: In this single-center retrospective study, adult patients followed with a diagnosis of sarcoidosis between January 2014 and June 2024 were reviewed. Patients with concomitant infection at diagnosis, HIV infection, active malignancy, hematologic disease, coexisting tuberculosis, or missing clinical/laboratory data were excluded. Baseline complete blood count parameters were used to calculate NLR and PLR values. Relapse status during follow-up was recorded, and laboratory parameters at relapse were additionally evaluated in relapsing patients. Group comparisons, ROC analyses, and multivariate logistic regression analyses were performed to evaluate the association between inflammatory indices and relapse.Results: A total of 198 patients were included, and relapse occurred in 32 patients (16.2%). Patients with relapse had significantly higher baseline NLR (median 2.6 vs 2.1, p=0.003) and PLR (median 208.6 vs 132.3, p