Treatment outcome of patients with smear-negative and smear-positive pulmonary tuberculosis in the National Tuberculosis Control Programme, Malawi

National tuberculosis control programmes (NTPs) in sub-Saharan Africa do not routinely record or report treatment outcome data on smear-negative pulmonary tuberculosis (PTB) patients. Twelve-month treatment outcome on patients with smear-negative PTB registered in all district and mission hospitals in Malawi during the year 1995 was collected, and was compared with 8-month treatment outcome in smear-positive PTB patients registered during the same period. Of 4240 patients with smear-negative PTB, 35% completed treatment, 25% died, 9% defaulted and 7% were transferred to another district with no treatment outcome results available. In 24% of patients treatment cards were lost and treatment outcome was unknown. These results were significantly inferior to those obtained in 4003 patients with smear-positive PTB in whom 72% completed treatment, 20% died, 4% defaulted, 2% were transferred and 1% had positive smears at the end of treatment. These differences between patients with smear-negative and smear-positive PTB were similar when analysed by sex and by most age-groups. Higher mortality rates in patients with smear-negative PTB are probably attributable to advanced HIV related immunosuppression, and higher default and treatment unknown rates probably reflect the lack of attention paid by TB programme staff to this group of patients. As a result of this country-wide study the Malawi NTP has started to record routinely the treatment outcomes of smear-negative TB patients and has set treatment completion targets of 50% or higher for this group of patients.