Clinical Characteristics Of Tuberculous Pleurisy Patients With Low Adenosine Deaminase Levels

Abstract

Background: The levels of adenosine deaminase (ADA) are increased in most tuberculous pleural effusions, and this is very useful for differentiating tuberculous pleurisy from non-tuberculous pleural effusion. However, some cases of tuberculous pleural effusion show decreased levels of ADA. This study aimed to investigate the differences in clinical characteristics between high and low ADA level groups. Methods: From January 2004 to September 2008, 139 adult patients with tuberculous pleurisy admitted to the Gyeongsang National University Hospital were enrolled in the study. Patients were divided into two groups based upon their pleural fluid ADA levels; a low ADA (<40IU/L) group (n=17) and a high ADA (≥40 IU/L) group (n=122). The medical records were analyzed retrospectively. Results: A total of 139 patients were enrolled in this study (mean age=51.2±20.4, M: F=92:47). The mean age was higher in the low ADA group than the high ADA group(64.8±8.6:49.5±20.9, P<0.001) and showed a significant negative correlation with ADA levels (r=-0.271, p=0.001). In addition, the percentages of patients with a history of tuberculosis (47.1%:14.6% P=0.004) and current smokers (52.9%:28.5%, P=0.003) were higher in the low ADA group than the high ADA group. There were no significant differences for sex, radiologic finding, pulmonary function and treatment outcomes between the two groups. Conclusion: Tuberculous pleurisy patients with low ADA levels tend to be older and there is a higher percentage of current smokers and past history of tuberculosis in this group compared with the high ADA group.