ABSTRACT: BACKGROUND:Tunnelled pleural catheters used to treat malignant pleural effusions may achieve pleurodesis. We aimed to identify factors associated with higher pleurodesis rates and earlier catheter removal. METHODS:We retrospectively reviewed a prospective database of tunnelled pleural catheters inserted consecutively between May 2006 and June 2013 for confirmed malignant pleural effusion. The cohort included patients who underwent medical thoracoscopy. Clinical, radiologic and pleural fluid data were recorded. We used logistic regression and Cox regression to assess rates of and days to pleurodesis, respectively. RESULTS:We analyzed data for 1071 tunnelled pleural catheters in 956 patients. Increased rates of pleurodesis were associated with lymphoma (odds ratio [OR] 3.49, 95% confidence interval [CI] 1.93-6.33), ovarian cancer (OR 2.93, 95% CI 1.68-5.11), Eastern Cooperative Oncology Group Scale of Performance Status grade 2 or less (OR 2.79, 95% CI 1.79-4.34), medical thoracoscopy (OR 2.21, 95% CI 1.28-3.85), protein level (OR 1.03, 95% CI 1.01-1.06), albumin level (OR 1.07, 95% CI 1.03-1.12) and percent eosinophils (OR 1.04, 95% CI 1.00-1.07). Reduced rates of pleurodesis were associated with gastrointestinal cancers (OR 0.41, 95% CI 0.19-0.87), hydropneumothorax on the postdrainage chest radiograph (OR 0.62, 95% CI 0.41-0.94) and percent other cells on cell count (OR 0.98, 95% CI 0.97-0.99). Earlier pleurodesis was associated with ovarian cancer (hazard ratio [HR] 1.48, 95% CI 1.06-2.08), medical thoracoscopy (HR 1.45, 95% CI 1.10-1.92), protein level (HR 1.03, 95% CI 1.01-1.04) and percent eosinophils (HR 1.02, 95% CI 1.00-1.04). Delayed pleurodesis was associated with breast cancer (HR 0.61, 95% CI 0.46-0.81), hydropneumothorax with 80% or less lung expansion (HR 0.55, 95% CI 0.38-0.80) and percent other cells (HR 0.99, 95% CI 0.98-1.00). INTERPRETATION:Clinicians should consider numerous factors to predict the probability of and timing to pleurodesis with tunnelled pleural catheters.