Factors Predicting Sputum Smear Conversion and Treatment Outcomes in New Smear-Positive Pulmonary Tuberculosis
Somkid Unsematham MD*, Pairaj Kateruttanakul MD*
Affiliation : * Department of Medicine, Rajavithi Hospital, College of Medicine, Rangsit University, Bangkok, Thailand
Background : Epidemiological studies indicated that the proportion of TB patients who remained smear-positive after
two months of treatment could be greater than 20%. The lack of smear conversion in the second month of treatment was
one of the predictors of treatment failure and relapse.
Objective : To determine factors associated with the persisting positive smear after two months of treatment and its value
in predicting treatment failure.
Material and Method: A 3-year retrospective cohort study was conducted in a 1,200-bed government hospital in Thailand.
New smear-positive tuberculosis patients who had pretreatment drug susceptibility test, the result of 2-month sputum smear,
and treatment outcomes were selected. The pretreatment drug susceptibility pattern and statistically differences on variables
between groups of patients were described.
Results : Three hundred fifty six patients were included in the present study. The level of pretreatment isoniazid resistance
and multi-drug resistance were 13.8% and 3.1% respectively. Factors associated with the 2-month positive smear were
male sex, high initial sputum acid-fast bacilli grades, and cavitary diseases. The presence of human immuno-deficiency
virus infection, drug resistance and the 2-month positive smear were significantly associated with treatment failure.
Conclusion : Male sex, high initial sputum acid-fast bacilli grades, and cavitary diseases were factors associated with the
2-month positive smear and increasing risk of treatment failure.
Keywords : Sputum conversion, Treatment failure
