Methods: The prospective study included 125 patients (67 males, 58 females; median age: 62 years; range, 40 to 92 years) who underwent thoracentesis for pleural effusion between January 2020 and December 2021. An overall survival analysis was performed, and survival differences between the groups were investigated. The cutoff value of the inflammatory parameters associated with mortality was determined by receiver operating characteristic analysis.

Results: Median survival after detection of MPE was six months, and three- and five-year overall survivals were 16% and 4%, respectively. There was a significant correlation between the ECOG (Eastern Cooperative Oncology Group) score of the patients and the median survival. Serum C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), fluid albumin, and serum lactate dehydrogenase (LDH)-to-pleural LDH ratio and survival had a statistically significant relationship in receiver operating characteristic analysis. Threshold values were determined accordingly. Poor prognostic factors that were found to be statistically significant were high CRP (p=0.001), high NLR (p=0.001), high PLR (p=0.02), and high serum LDH-to-pleural LDH ratio (p=0.04).

Conclusion: Some serum inflammatory markers, including high CRP, high NLR, high PLR, and high serum LDH-to-pleural LDH ratio, can be a simple and inexpensive method in predicting prognosis in patients with MPE.