Conversion rate at two-month follow-up of smear-positive tuberculosis patients in Burkina Faso.

SETTING: Burkina Faso, West Africa. OBJECTIVE: 1) To determine the trend of sputum smear conversion rates at the 2-month follow-up of new smear-positive tuberculosis (TB) patients; and 2) to compare conversion rates in cured TB patients and treatment failures. DESIGN: Retrospective cohort study based on TB registers from all 80 diagnostic and treatment centres from 1995 to 2003. The conversion rate was defined as the number of negative results divided by the number of smear-positive patients for whom the 2-month follow-up examination was completed. RESULTS: The 2-month follow-up completion rate was 92.1%; it increased from 86.3% in 1996 to 94.3% in 2003. The conversion rate was 82.9%, increasing from 76.3% in 1995 to 87.9% in 1997 and falling to 80.3% in 2003. The cure rate was higher among patients who were smear-negative at the 2-month follow-up (77.3%) CONCLUSION: The conversion rate was satisfying, but had declined since 1997, which may be a matter of concern. This could be due to patient characteristics such as associated conditions (human immunodeficiency virus, malnutrition) or to drug management (ineffective administration of drugs even under directly observed treatment, insufficient dosages, resistance). Thorough research is needed to elucidate this negative trend.