Predicting Time to Next Procedure in Patients with Malignant Pleural Effusion Undergoing Therapeutic Aspiration: Derivation and Validation of the RED Score.

Abstract

Background: In patients with malignant pleural effusions (MPEs), pleural fluid reaccumulates at variable rates following therapeutic aspiration. We aimed to derive and validate a clinical score to predict time to next procedure. Methods: This prospective observational cohort study in 10 UK hospitals recruited patients with known or suspected MPE undergoing therapeutic aspiration. Follow up was for 3 months, with time of next clinically indicated pleural procedure recorded. Regression analysis was performed to identify independent variables predicting time to next procedure, and a score derived and validated in two independent cohorts. Findings: 241 patients were recruited. Within the discovery cohort, baseline respiratory rate (R), pleural effusion depth on ultrasound (E) and dyspnoea measured using a visual analogue scale (D) (combined to form the RED score) were independent predictors of time to next procedure. Predictive models provided areas under the ROC of 0.73 and 0.75. The score demonstrated validity in the external cohorts. Analysis of the original cohort demonstrated that: 54% of patients with a high RED score had a further procedure within 2 weeks; 42% of those with a medium RED score had a further procedure in 2-6 weeks; and 61% of those with a low RED score after 6 weeks. Interpretation: The RED score is a simple score which predicts time to next procedure in patients with known or suspected MPE undergoing therapeutic aspiration. Further research is required to determine whether use of the RED score in clinical practice can improve patient pathways and outcomes.