Supplementary Material for: Repeat Thoracentesis in Hepatic Hydrothorax and Non-Hepatic Hydrothorax Effusions: A Case-Control Study

Background: Repeat thoracentesis for symptom control is offered to patients with refractory hepatic hydrothorax (HH) but the risk profile for this management strategy remains unclear. Objectives: This study aimed to compare complication frequency and nature during repeat thoracentesis in patients with and without HH. Methods: Complication rates in patients undergoing repeat thoracentesis for symptom relief was compared between patients with HH and a control group (non-HH group) at a single center from 2010 to 2015. Records were reviewed for demographics, laboratory values, number of thoracentesis, and associated complications with each procedure. Results: 82 patients with HH (274 thoracenteses) and 100 control patients (188 thoracenteses) were included. A complication was noted in 17/462 (0.03%) procedures in the entire cohort. There was a higher overall complication rate with repeat thoracentesis in the HH group (8 vs. 0%, p = 0.016, 95% CI = 1.5–14.6). In the HH group, the cumulative risk of complications increased with sequential thoracenteses; a complication occurring in the preceding intervention was the strongest predictor for subsequent complication (OR = 17.1, p = 0.0013) and more than 1 previous complication was associated with a 15-fold increased risk of a subsequent complication (p < 0.001). In multivariate analysis within the HH group, the Model for End-Stage Liver Disease (MELD) score was an independent predictor of hemothorax (OR = 1.19, 95% CI = 1.03–1.36, p = 0.012). Conclusions: Repeat thoracentesis is an overall low-risk procedure, although a higher complication rate is observed in HH compared with non-HH patients. The presence of a previous complication significantly increases the risk of future complications in the HH population.