Factors influencing pleural adenosine deaminase level in patients with tuberculous pleurisy.
BACKGROUND
Adenosine deaminase (ADA) activity is useful for diagnosing tuberculous (TB) pleurisy in regions with a high prevalence of tuberculosis. However, some cases of TB pleural effusion show decreased ADA activity. Therefore, we evaluated factors influencing pleural ADA levels in patients with TB pleurisy.


METHODS
We retrospectively evaluated 182 patients with TB pleural effusion who were admitted to Gyeongsang National University Hospital from January 2004 to September 2008. Patients were dichotomized into 2 groups: a low-ADA (<40 IU/L) group (n = 22) and a high-ADA (≥40 IU/L) group (n = 160). Age, sex, ADA level of pleural effusion, smoking status, history of tuberculosis and comorbid diseases were evaluated in each group.


RESULTS
The median age of the patients was 50.5 years, with a male to female ratio of 1.72:1. Patients with a low-ADA level were significantly older than those with a high ADA level (66.9 ± 12.0 versus 49.4 ± 21.2 years, P < 0.001). A history of tuberculosis and hypertension was more common in the low-ADA group than in the high-ADA group (31.8% versus 15.0%, P = 0.049 and 36.4% versus 16.9%, P = 0.03, respectively). A multivariate analysis revealed that older age and current smoking were predictive of TB pleurisy with a low ADA level (odds ratios, 1.053 and 4.848; P = 0.002 and 0.028, respectively).


CONCLUSIONS
Physicians should be careful when interpreting pleural ADA levels in elderly patients and/or current smokers for the diagnosis of TB pleurisy.
Division of Pulmonology and Allergy (SJL, SHL, TWL, HRL, YJC, YYJ, HCK, JDL, YSH), Department of Internal Medicine, College of Medicine, Gyeongsang National University, Jinju, Republic of Korea; and Department of Internal Medicine (HSK), Seran Hospital, Jinju, Republic of Korea.
Seung Jun
SJ
Lee
Hyun Sik
HS
Kim
Seung Hun
SH
Lee
Tae Won
TW
Lee
Hyang Rae
HR
Lee
Yu Ji
YJ
Cho
Yi Yeong
YY
Jeong
Ho Cheol
HC
Kim
Jong Deog
JD
Lee
Young Sil
YS
Hwang
D000243:Adenosine Deaminase / Q000378:metabolism*; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000175:diagnosis* / Q000201:enzymology*; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects / Q000378:metabolism; D014396:Tuberculosis, Pleural / Q000175:diagnosis* / Q000201:enzymology*
D000243:Adenosine Deaminase