An elevated neutrophil lymphocyte ratio is a poor prognostic marker in all categories of pleural effusions

Introduction/Aim: Neutrophil lymphocyte ratio (NLR) has demonstrated utility in predicting prognosis in patients with solid organ malignancies, with a recent systematic review suggesting that a NLR >4 is associated with poor prognosis. The role of NLR in non-malignant disorders has not been as extensively evaluated. The utility of NLR in predicting prognosis in patients with malignant and benign pleural effusions has not been previously evaluated. Methods: Retrospective analysis was performed on all patients undergoing diagnostic pleural aspiration over a 24 month period. Data were collected from medical records, radiology and pathology databases. Pleural effusions were considered malignant if pleural cytology was positive, a tissue biopsy was positive for malignancy, or if subjects had disseminated malignancy with no alternative explanation for the effusion. Statistical analysis was performed using SPSS Version 21. Results were considered significant at p 4 or Results: We analysed data sets from 60 patients who underwent diagnostic pleural aspiration. 23 (38%) had malignant effusions and 37 (62%) had benign effusions. The NLR was not different between groups(p=0.982). An NLR >4 was associated with a longer length of stay; 13 ± 2.2 (SEM) days versus 4.6 ± 0.83 (SEM) days (p=0.005) and reduced overall survival; 8.4 ± 1.1(SEM) months versus 12.9 ± 1.5 (SEM) months (p=0.023). Conclusion: NLR is a poor prognostic marker in patients with pleural effusions. An NLR >4 is associated with a longer length of inpatient hospital stay and reduced overall survival.