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

Abstract

To examine the effect of HIV on response to treatment and recurrence rate in patients with tuberculosis (TB), we have followed 239 previously untreated, adult, TB patients in a prospective cohort study in Lusaka, Zambia. One hundred and seventy-four (73%) were HIV-1 antibody positive. Patients with sputum smear positive, miliary, or meningeal TB were prescribed 2 months daily streptomycin, thiacetazone, isoniazid, rifampicin, pyrazinamide followed by 6 months thiacetazone and isoniazid; others, 2 months streptomycin, thiacetazone and isoniazid followed by 10 months thiacetazone and isoniazid. Thirty-five per cent of HIV-positive (HIV+ve) and 9% of HIV-negative (HIV-ve) patients were known to have died before the scheduled end of treatment. Surviving HIV+ve patients showed weight gain and improvement in symptoms and laboratory and radiological findings similar to HIV-ve patients. The risk of cutaneous drug reaction was 17% (95% CI: 12-25%) in HIV+ve, and 4% (1-13%) in HIV-ve patients. Severe rashes were attributed to thiacetazone. Recurrence of active TB was examined among 64 HIV+ve and 37 HIV-ve patients who successfully completed treatment, with mean follow-up after the end of treatment of 13.5 and 16.8 months, respectively. The rate of recurrence was 22/100 person years (pyr) for HIV+ve patients and 6/100 pyr for HIV-ve patients, giving a recurrence rate ratio of 4.0 (95% CI 1.2-13.8, P = 0.03).

PIP: 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.