Characteristics and negative impacts of pleural effusion in hospitalized patients undergoing maintenance hemodialysis.

Background: Hospitalized patients on maintenance hemodialysis often develop pleural effusion (PE). The prognosis of these patients is likely to be affected by the PE. This study examined the characteristics of PE, identified risk factors for its development, and explored its negative effects.

Methods: In this retrospective study, we analyzed medical records of 1,077 patients who underwent maintenance hemodialysis between October 2014 and January 2022. According to the chest computed tomography (CT) imaging results, patients were categorized into two groups: PE and non-PE. A definitive diagnosis of PE was made after a nephrologist, a pulmonary physician, and a radiologist reviewed the case.

Results: Of the 1,077 patients, 343 (31.85%) were diagnosed with PE. These patients had a mean age of 55.28±15.21 years old and 61.47% of them were men. There were 77.84% patients with PE resulting from heart failure, and 82.02% of these patients had bilateral effusions. The occurrence of PE was associated with cardiovascular disease, clinic-systolic blood pressure (SBP), chest tightness, leg edema, and pro-brain natriuretic peptide (pro-BNP). PE patients had a poorer survival rate than patients without PE (unadjusted hazard ratio [HR]: 4.17; 95% CI: 3.12-5.57). The survival rates of patients with small PE did not differ from those with moderate to large PE. Similarly, no difference was found in survival between the bilateral PE and unilateral PE groups, as well as between the heart failure and non-heart failure groups.

Conclusions: Hospitalized patients undergoing maintenance hemodialysis have a high incidence of PE. PE (even a small amount) is an risk factor for increased mortality. These poor prognostic features should be noted by physicians and managed accordingly.