Diagnostic and Prognostic Value of Systemic Inflammatory Markers and Serum Vitamin D in <scp>CRS</scp>

ABSTRACT Objective To evaluate the prognostic role of systemic inflammatory markers and vitamin D in chronic rhinosinusitis (CRS) and to establish predictive models for eosinophilic CRS (ECRS) based on the clinical characteristics. Methods Retrospective analysis of data from 1072 CRS patients and 229 controls identified CRS and ECRS risk factors using systemic inflammatory markers and serum 25‐hydroxyvitamin D (25(OH)D), with all analyses performed on propensity score‐matched (PSM) cohorts. Logistic regression constructed an ECRS prediction model, evaluated by the receiver operating characteristic (ROC) curve's area under the curve (AUC). Kaplan–Meier (K‐M) curve assessed serum 25(OH)D's prognostic impact on CRS. Cox regression identified CRS prognostic factors and built a nomogram model, with accuracy assessed by the ROC curve and Harrell's concordance index ( C ‐index). Results Logistic regression showed increased eosinophil‐to‐lymphocyte ratio (ELR), decreased serum 25(OH)D, and concomitant polyps were ECRS predictors (all p &lt; 0.05), incorporated into the nomogram prediction model with AUC = 0.858. The K‐M curve showed poor prognosis of CRS patients with VD deficiency ( p = 0.024). Cox regression identified absolute eosinophil count (EOS#), lymphocyte percentage, platelet‐to‐lymphocyte ratio (PLR), platelet distribution width (PDW), osteitis score, and decreased serum 25(OH)D levels as independent prognosis predictors in CRS (all p &lt; 0.05), included in a nomogram predictive model with a C ‐index of 0.724. AUC values were 0.962, 0.750, and 0.814 at 12, 18, and 24 months post‐surgery. Conclusions Elevated EOS#, lymphocyte percentage, PLR, PDW, osteitis score, and decreased serum 25(OH)D levels predict poor prognosis in CRS. Incorporating these factors enhances predictive accuracy. Combining ELR, serum 25(OH)D levels, and concomitant polyps may improve ECRS prediction. Level of Evidence 3