Factors Affecting Discordance between Sputum Smear and Culture Conversion Rates In Newly Diagnosed Pulmonary Tuberculosis: A Retrospective Study in Developing Country.
To assess the performance of sputum AFB smear for monitoringtreatment response and outcome of anti-tuberculous drugs among newly diagnosed smear positive pulmonary TB patients. Study
Design:
This study was conducted prospectively among newly diagnosed smear positive pulmonary TB patients. Place and Duration of Study Queen Savang Vadhana Memorial Hospital and Chonburi Regional Hospital, Chonburi province, Thailand during April 2010 and July 2012.
Of 297 eligible pulmonary TB cases, majorities were male (72.4%) with median age of 39 years, illiterate to low educated (52.6%) and earning low income (77.5%). Cough was the most common symptom (91.2%) and cavity was present in 31.1%. At the second month, 17.0% of patients had discordance between sputum AFB smear and culture. High bacilli load (adjusted OR=2.38, CI=1.09-5.18), and hearing alteration (adjusted OR=10.98, CI=1.79-67.28) were significant predictors. Hypoalbuminemia was significantly more severe in patients with false positive AFB smear (P=.04). Sensitivity and specificity for AFB smear were 44.7% and 89.6% at the second month and 57.1% and 97.5% at the fifth month, respectively. MDR-TB was diagnosed in 1.0% and success rate was 77.1%.
Conclusions:
Baseline AFB smear ≥ 2+ and hypoalbuminemia as well as adverse events during intensive phase are strongly recommended as the criteria to prioritize culture and DST for new smear positive pulmonary TB patients with positive AFB smear at the second and the third month of treatment in developing countries.