Risk factors for new pulmonary tuberculosis patients failing treatment under the Revised National Tuberculosis Control Programme, India.

SETTING

Tertiary level tuberculosis (TB) institute in Delhi, India.

OBJECTIVE

To study the risk factors for new pulmonary TB (PTB) patients failing treatment.

DESIGN

Prospective case-control study. The profile of new PTB patients failing treatment (i.e., sputum smear-positive at 5 months of treatment) and responders under the Revised National Tuberculosis Control Programme (RNTCP) were compared and risk factors associated with treatment failure were analysed.

RESULTS

A total of 42 treatment failure cases and 76 controls were enrolled in the study. The presence of cavity on chest X-ray (CXR), sputum acid-fast bacilli (AFB) smear positivity at 2 months of treatment and the number of interruptions in treatment were independently associated with failures. Among failure patients at 5 months, 17 (40.5%) had negative sputum culture for Mycobacterium tuberculosis, and only six (14.3%) had multidrug-resistant TB (MDR-TB). When put on retreatment, patients with smear-positive, culture-negative sputum had cure rates of 88.2% compared to 28.6% among culture-positive patients.

CONCLUSIONS

The presence of cavity on CXR, sputum smear positivity at 2 months of treatment and the number of interruptions of treatment are risk factors for failure. Among failures based on smear examination, the prevalence of MDR-TB is low and many patients have negative cultures for M. tuberculosis. Smear positivity at the end of treatment may not be a reliable indicator of treatment failure.