The impact of human immunodeficiency virus on response to treatment and recurrence rate in patients treated for tuberculosis: two-year follow-up of a cohort in Lusaka, Zambia

In 1989 researchers followed 239 newly diagnosed adult patients with tuberculosis (TB) never previously treated for TB for two years to examine the response to TB treatment among patients with and without HIV infection and the TB recurrence rate. They were patients in the medical wards and the chest clinic outpatients department of the University Teaching Hospital in Lusaka Zambia. 174 (73%) tested positive for HIV. HIV-positive patients were more likely than HIV-negative patients to have extrapulmonary and both pulmonary and extrapulmonary TB (35% and 26% for both respectively vs. 17% and 12% respectively; p < 0.001). They were less likely to have positive sputum tests than HIV-negative patients (36% vs. 57% for smear; p = 0.005 and 39% vs. 55% for culture; p = 0.03). HIV-positive patients were more likely to receive standard TB therapy (62% vs. 37%) while HIV-negative patients were more likely to receive short course therapy (62% vs. 37%; p = 0.001). HIV-positive patients were more likely than HIV-negative patients to die before completion of treatment (35% vs. 9%). Surviving HIV-positive patients gained weight and experienced improvement in symptoms at the same rate as did surviving HIV-negative patients. They also had similar laboratory and radiological findings. HIV-positive patients had a higher risk of cutaneous drug reaction than HIV-negative patients (17% vs. 4%; hazard ratio = 5.1; p = 0.03). One HIV-positive patient with a rash died. Thiacetazone was responsible for the rashes. Among the HIV-positive and HIV-negative patients who successfully completed treatment the active TB recurrence rate was greatest for HIV-positive patients (22 vs. 6/100 person years; rate ratio = 4; p = 0.03). Yet all but one of the HIV-positive cases with recurrent TB responded well to TB treatment. High recurrence rates pose renewed potential sources of infection and a high cost of renewed treatment.