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

Lilongwe Central Hospital, Malawi.

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.

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.

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).

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.