Older Age and Diabetes Mellitus Decrease the Presence of Sonographic Septations Independent of Tuberculous Pleuritis

Abstract

PURPOSE: Pleural ultrasound can be readily done at the bedside by pulmonologists, and has both diagnostic and prognostic value in tuberculous pleuritis. The presence of sonographic septations may distinguish tuberculous from malignant effusions, and may predict residual pleural thickening after anti-tuberculosis treatment. However, it is unclear if age and other comorbidities can affect the presence of sonographic septations. METHODS: We performed a retrospective analysis of all exudative pleural effusions with known etiologies referred to our pulmonology unit between 2007 and 2010. Transudates and effusions presumed but not proven to be tuberculous pleuritis were excluded. Pleural effusions were divided into two groups: tuberculous pleuritis (group A, with positive Mycobacterium tuberculosis cultures from pleural fluid, pleural biopsy, or sputum) and others (group B). Logistic regression was done using age, gender, and comorbidities (diabetes mellitus, chronic heart failure, chronic obstructive pulmonary disease, chronic renal failure) to predict sonographic septations (yes/no), adjusted for diagnostic group (A/B). RESULTS: Two hundred and eighteen exudative pleural effusions belonging to 215 patients were analyzed (three patients had repeated and distinct hospitalizations). Seventy-seven effusions (35.3%) had sonographic septations. There were 32 group A effusions. Among 186 group B effusions, there were 94 diagnosed as parapneumonic effusion/empyema, 80 as malignant pleural effusion (predominantly primary lung adenocarcinoma), three as pulmonary embolism, three as hemothorax, three as asbestosis, two as congenital lymphedema, and one as uremic pleuritis. Adjusting for diagnostic group, older age decreased the presence of ultrasonographic septations by 19% per decade (OR 0.81, 95% CI 0.67-0.97, p=0.026), while the presence of diabetes mellitus decreased the presence of septations by 59% (OR 0.41, 95% CI 0.17-0.97, p=0.042). Gender, chronic heart failure, chronic obstructive pulmonary disease and chronic renal failure did not significantly affect the presence of septations. CONCLUSIONS: Older age and diabetes mellitus decreased the presence sonographic septations, independent of tuberculous pleuritis.