Multi-index retrospective analysis of eosinophilic pleural effusion

Background:Eosinophilic pleural fluid is a unique type of pleural fluid, the causes of which need to be further studied. In this study, a number of test indicators were collected to understand the characteristics of eosinophilic pleural effusion to better analyze eosinophilic pleural effusion and provide useful information for clinical practice. Methods: A retrospective analysis was performed by examining the medical records of 2769 patients with pleural fluid (PE) from September 2013 to January 2024. Blood routine, blood biochemistry, coagulation, pleural fluid routine, and pleural fluid biochemistry data of these patients were collected and analyzed. At the same time, 9 categories of etiologies of eosinophilic pleural effusion were classified, and their characteristics were analyzed. Results: When 2769 cases of pleural effusion were examined and categorized, 461 cases ofeosinophilic pleural effusion (EPE) were identified. Among these EPE cases, 213 were associated with tumors, with lung cancer constituting 63.85% of these tumors, thus emerging as the primary cause of EPE. Furthermore, among the EPE patients, indicators such as D-D, TT, ALP, TBIL, GGT, GLU, LDH, PB-WBC, PB-LYM, PB-PLT, PF-WBC, PF-NEU, PF-MON, ALT, and AST did not significantly differ (p value>0.05), whereas other indicators did. Within the EPE group, the parasitic subgroup had the highest median levels of PB-EOS% and PF-EOS% across the nine etiological categories. When comparing EPE with non-EPE (n-EPE), in addition to FIB, UA, PF-RBC, ADA, and ALT, which were not significantly different, theother indicators were significantly different. In the correlation analysis, 11 sets of data within the EPE group had correlation coefficients with absolute values greater than 0.6. By applying an 8% threshold for PB-EOS%, the 461 cases of EPE were divided into two groups, revealing significant differences in Age, D-D, TP, PF-TP, UA, ALB, PF-ALB, PF-LDH, PB-WBC, PB-NEU, PB-EOS%, PB-RBC, PB-HCT, PF-WBC, PF-EOS%, PF-LYM, and ADA. Conclusions: Lung cancer is the main cause of eosinophilic pleural effusion, but parasitic infection is the most prominent factor influencing the percentage of eosinophils in the pleural fluid (PF-EOS%). The theory of eosinophilic pleural effusion needs to be further refined and enriched to improve clinical diagnosis and treatment.