Table II.

Logistic regression analysis of factors significantly associated with sputum M. tuberculosis culture positivity.

Factor	Point estimate	Standard error	Wald Chi-square	Odds P-value	95% CI ratio for odds ratio
Severity of clinical presentation	1.01	3.68	9.61	<0.01	2.74	1.04–7.22
Sputum ET-1 level (pg/ml)	1.87	0.49	4.17	0.04	6.50	1.32–32.02

Multivariate logistic regression analysis was performed with sputum culture results (M. tuberculosis negative=0, M. tuberculosis positive=1) as the dependent variable. Age, gender (female=0, male=1), severity of clinical presentation (mild=1, moderate=2, severe=3), sputum ET-1 level, plasma ET-1 level, and co-morbidities (hypertension and/or coronary artery disease, no=0, yes=1; chronic bronchitis and/or COPD, no=0, yes=1) were used as independent variables. Severity of clinical presentation and sputum ET-1 level entered the logistic regression model. M. tuberculosis, Mycobacterium tuberculosis; ET, endothelin; CI, confidence interval.