Effect of isoniazid prophylaxis on incidence of active tuberculosis among Thai HIV-infected individuals

Abstract

A prospective comparative study was conducted to determine the effect of isoniazid prophylaxis on the incidence of active tuberculosis among Thai HIV-infected patients for 1 year. Among those 36 HIV-infected patients without prophylaxis, the incidence of active tuberculosis was 2.7 per cent while in 10 HIV-infected patients with isoniazid prophylaxis, there was no incidence of active tuberculosis during the first year.

PIP: In Thailand during 1994-1995, 46 HIV-seropositive asymptomatic patients were followed-up monthly for 1 year to evaluate the prophylactic effect of isoniazid against tuberculosis among these patients. 36 patients did not receive isoniazid; the remaining 10 patients received 300 mg isoniazid daily for 1 year. The 2 groups were matched for age and sex. Three controls and 1 case dropped out of the study during the second half. Only 1 (2.7%) of the controls developed active tuberculosis. Active tuberculosis in this case developed on the fifth month of follow-up. This patient responded well to anti-tuberculosis drugs (300 mg isoniazid, 600 or 450 mg rifampicin depending on weight, 20-30 mg/kg pyrazinamide daily, and 1 g streptomycin daily for 2 weeks and 15 mg/kg thereafter). No cases developed active tuberculosis. Despite study weaknesses (e.g., low sample size), prophylactic isoniazid is recommended for HIV-positive asymptomatic patients.