Clinical characteristics and prognostic factors of non-malignant pleural effusions in hospitalised patients: a retrospective cohort study

Objective Non-malignant pleural effusions (NMPE) are common in hospitalised patients. Data on NMPE inpatients are scarce and the factors influencing the prognosis are unknown.Design This was a retrospective cohort study.Setting and participants We conducted a retrospective cohort of inpatients (n=86 645) admitted to the Chinese PLA General Hospital from 2018 to 2021, based on electronic medical records. The observations of 4934 subjects with effusions confirmed by chest radiological tests (CT or X-ray) without a diagnosis of malignancy were followed during admission. Logistic regression was used to analyse organ damage and other factors associated with in-hospital death. Patients were clustered according to their laboratory indicators, and the association between the clustering results and outcomes was studied.Outcome The outcome of this study was in-hospital mortality.Results Among 4934 patients, heart failure + pneumonia + renal dysfunction was the most common (15.12%) among 100 different diagnostic groups. 318 (6.4%) patients died during hospitalisation. Lung (OR 3.70, 95% CI 2.42 to 5.89), kidney (OR 2.88, 95% CI 2.14 to 3.90) and heart (1.80, 95% CI 1.29 to 2.55) damage were associated with in-hospital mortality. Hierarchical clustering of laboratory indicators (estimated glomerular filtration rate, white blood cell count, platelet count, haemoglobin, N-terminal pro-B-type natriuretic peptide, serum albumin) demonstrated the ability to discriminate patients at high risk of in-hospital death.Conclusion Comorbidities and multiorgan failure are the prominent characteristics of NMPE patients, which increase the risk of in-hospital mortality, and comprehensive intervention for specific comorbidity patterns is suggested.