'Smear-negative' pulmonary tuberculosis in a DOTS programme: poor outcomes in an area of high HIV seroprevalence.

Setting: Lilongwe Central Hospital, Malawi.

Objectives: To investigate 1) treatment outcome of a cohort of smear-negative pulmonary TB (snPTB) patients in an area of high human immunodeficiency virus (HIV) seroprevalence, and 2) whether poor treatment outcomes are due to non-TB patients being mistakenly treated for TB due to lack of diagnostic facilities.

Design: Patients about to be registered for snPTB treatment by the National TB Programme underwent further assessment including TB culture, bronchoscopy and bronchoalveolar lavage. All patients were followed up for 8 months. Standard TB control treatment outcomes were recorded.

Results: Of 352 snPTB patients assessed, 137 patients had bacteriologically confirmed TB, 136 had possible TB, and 79 had other non-TB diagnoses. The HIV seroprevalence rate was 89%. Outcomes were known for 325 (92%) patients: 129 (40%) died within 8 months. Death rates on TB treatment were 31% for bacteriologically confirmed TB patients and 35% for patients with possible TB but no bacteriological diagnosis. The death rate among patients with non-TB diagnoses was 53%. HIV infection significantly increased the risk of death (OR 3.9; P = 0.01).

Conclusion: SnPTB is strongly associated with HIV infection in Malawi, where patients treated for snPTB have a poor prognosis. The high mortality is not fully explained by non-TB patients being mistakenly treated for TB.