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

Abstract

The frequency of "complicated" pleural effusions (CPE) (i.e., pleural fluid pH≤7.2 and/or glucose ≤60mg/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). 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%. 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 (<46IU/L [0 points], 46-100IU/L [4 points], ≥100IU/L [6 points]), MNC% (<10% [0 points], 10-50 [3 points], >50 [8 points]), pH (<7.07 [0 points], 7.07-7.20 [3 points], >7.20 [5 points]), and age (≥30 [0 points], <30years [3 points]). A sum of 12 or more points had 97% sensitivity, 92% specificity, likelihood ratio positive 12.3, likelihood ratio negative 0.03, and area under the curve of 0.947 for identifying CTPE versus CPPE in the validation set. CPE is not an unusual presentation of tuberculosis. A simple new scoring system provides a reliable tool for differentiating between CTPE and CPPE.