Development and Validation of the COMPLES Score for Differentiating Between Tuberculous Effusions with Low Pleural pH or Glucose and Complicated Parapneumonic Effusions

Background The frequency of “complicated” pleural effusions (CPE) (i.e., pleural fluid pH ≤ 7.2 and/or glucose ≤60 mg/dL) of tuberculous origin (CTPE) is not well reported. This study aims to quantify their prevalence, and develop a score to differentiate CTPE from complicated parapneumonic effusions (CPPE). Methods Retrospective analysis of databases from three Spanish hospitals which included patients with CTPE and CPPE. Forty percent of the study population served to generate a scoring system (COMPLES, COMplicated PLeural Effusion Score) that was further validated in the remaining 60 %. Results During the study period (1992–2015) 549 patients were diagnosed with tuberculous effusions and 434 parapneumonic effusions, of whom 25 and 64 %, respectively, had CPE. COMPLES was based on the combination of pleural fluid adenosine deaminase (ADA), the percentage of mononuclear cells (MNC %), pH, and age. The cutoff values and assigned scores were: ADA (