Can red cell distribution width (RDW) and immature granulocyte parameters predict mortality in patients with pleural effusion?

Aims: Pleural effusion is a frequent clinical manifestation with variable etiologies and prognoses. Identifying reliable, accessible prognostic biomarkers is critical for early risk stratification. This study aimed to assess the prognostic significance of red cell distribution width (RDW) and immature granulocyte (IG) parameters in predicting in-hospital mortality in patients with pleural effusion. Methods: A retrospective analysis was conducted on 107 adult patients who underwent diagnostic thoracentesis. Hematologic data including RDW-CV, RDW-SD, IG percentage (IG%), and IG absolute count (IG#) were obtained within 24 hours of thoracentesis. Patients were categorized based on in-hospital survival status. Receiver operating characteristic (ROC) analysis was used to evaluate the predictive performance of these parameters. Results: In-hospital mortality occurred in 21.5% of patients. Non-survivors exhibited significantly higher RDW-CV, RDWSD, IG%, and IG# values (p<0.001 for all). RDW-CV demonstrated the highest prognostic accuracy (AUC=0.793), with an optimal cut-off value of 16.1% (sensitivity: 70.2%, specificity: 82.6%). RDW-SD showed an AUC of 0.782, with a cut-off of 55.8 fL (sensitivity: 88.1%, specificity: 60.9%). Among IG parameters, IG% (AUC=0.770) had a cut-off of 1.1% (sensitivity: 81.0%, specificity: 65.2%) and IG# (AUC=0.752) had a cut-off of 0.055×10³/μL (sensitivity: 61.9%, specificity: 87.0%). Conclusion: Elevated RDW and IG parameters independently predict in-hospital mortality in patients with pleural effusion. These readily available and cost-effective markers may serve as valuable tools for early prognostic assessment, particularly in settings where advanced diagnostic resources are limited.