DefinePK

Abstract

Sarcoidosis is a systemic granulomatous disease with diverse clinical phenotypes and natural histories, so there needs to identify potential biomarkers of disease severity. The aim of the study was to investigate the role of the platelet-to-lymphocyte ratio (PLR) as a biomarker to stop progressive treatment. PLR was found as a readily available haematological index relating to systemic inflammation in different chronic conditions; however, results were not uniform among studies conducted on sarcoidosis. In order to overcome these shortcomings, a prospective observational cohort study was carried out in the Department of Pulmonology Tertiary Care Hospital Karachi from January 2023 to June 2024. Eighty-two treatment-naïve, newly diagnosed sarcoidosis patients aged 18–70 years were recruited according to the ATS/ERS/WASOG diagnostic criteria. Detailed demographics, clinical presentation and laboratory findings were recorded on predesigned proformas. PLR was determined by the complete blood count, disease severity scoring, and staging Scadding using chest imaging and FVC/DLCO. Statistical analysis consisted of t-test, ANOVA, correlation, logistic regression and ROC curve analysis using SPSS version 27. PLR was higher in severe versus mild cases (214.3 ± 61.2 vs 138.6 ± 49.8, p < 0.001). PLR was positively correlated with ESR (r = 0.51, p < 0.001), CRP (r = 0.47, p < 0.001) and ACE (r = 0.36, p = 0.002), and negatively correlated with FVC (r = –0.58, p < 0.001) and DLCO (r = –0.55, P <.001). Logistic regression analysis revealed that both baseline PLR (OR = 1.012; p = 0.002) and CRP OR = 1.145; p = 0.021) were independently associated with severe sarcoidosis. A ROC analysis corroborated the accuracy of the diagnosis (AUC = 0.812; 95% CI 0.720–0.904) considering a best cut-off value equal to 176.5 that corresponded to a sensitivity – specificity set at 78.4 % and 74.6 %. These findings support PLR as an easily applicable and non-invasive tool for systemic action and severity of the disease that might have added value in less privileged settings.