Effect of isoniazid prophylaxis on mortality and incidence of tuberculosis in children with HIV: randomised controlled trial. Effect of isoniazid prophylaxis on incidence of active tuberculosis and progression of HIV infection. The use of isoniazid among household contacts of open cases of pulmonary tuberculosis. A controlled trial of isoniazid in persons with anergy and human immunodeficiency virus infection who are at high risk for tuberculosis. Terry Beirn Community Programs for Clinical Research on AIDS. Randomised controlled trial of isoniazid preventive therapy in South African adults with advanced HIV disease. Isoniazid preventive therapy for tuberculosis in HIV-1-infected adults: results of a randomized controlled trial. Isoniazid prophylaxis among Alaskan Eskimos: a final report of the bethel isoniazid studies. Twice weekly tuberculosis preventive therapy in HIV infection in Zambia. A trial of three regimens to prevent tuberculosis in Ugandan adults infected with the human immunodeficiency virus. Uganda-Case Western Reserve University Research Collaboration.
To investigate the impact of isoniazid prophylaxis on mortality and incidence of tuberculosis in children with HIV.
                Two centre prospective double blind placebo controlled trial.
                Children aged > or =8 weeks with HIV.
                Isoniazid or placebo given with co-trimoxazole either daily or three times a week.
                Two tertiary healthcare centres in South Africa.
                Mortality, incidence of tuberculosis, and adverse events.
                Data on 263 children (median age 24.7 months) were available when the data safety monitoring board recommended discontinuing the placebo arm; 132 (50%) were taking isoniazid. Median follow-up was 5.7 (interquartile range 2.0-9.7) months. Mortality was lower in the isoniazid group than in the placebo group (11 (8%) v 21 (16%), hazard ratio 0.46, 95% confidence interval 0.22 to 0.95, P=0.015) by intention to treat analysis. The benefit applied across Centers for Disease Control clinical categories and in all ages. The reduction in mortality was similar in children on three times a week or daily isoniazid. The incidence of tuberculosis was lower in the isoniazid group (5 cases, 3.8%) than in the placebo group (13 cases, 9.9%) (hazard ratio 0.28, 0.10 to 0.78, P=0.005). All cases of tuberculosis confirmed by culture were in children in the placebo group.
                Prophylaxis with isoniazid has an early survival benefit and reduces incidence of tuberculosis in children with HIV. Prophylaxis may offer an effective public health intervention to reduce mortality in such children in settings with a high prevalence of tuberculosis.
                Clinical Trials NCT00330304. Tuberculosis occurring with human immunodeficiency virus (HIV) infection is a serious and growing public health problem. We have carried out a randomised clinical trial of a 12-month course of isoniazid plus vitamin B6 versus vitamin B6 alone in Port-au-Prince, Haiti, to assess the efficacy of isoniazid in preventing active tuberculosis in symptom-free HIV-infected individuals. The effect of prophylaxis on the development of HIV disease, AIDS, and death was also investigated. 118 subjects were assigned treatment with isoniazid plus B6 (n = 58) or B6 alone (n = 60) between 1986 and 1989. The treatment groups were similar at study entry in demographic, clinical, and immunological characteristics. Interim analysis in 1990 revealed no significant difference in tuberculosis outcome measures. Follow-up was continued until 1992, at which time significant protection by isoniazid against the development of tuberculosis was apparent, both for the whole study population and for subjects positive for purified protein derivative of tuberculin (PPD). The incidence of tuberculosis was lower in isoniazid recipients than in patients who received B6 alone (2.2 vs 7.5 per 100 person-years). The relative risk of tuberculosis was 3.4 (95% CI 1.1-10.6) for B6 alone versus isoniazid plus B6 (p < 0.05). Isoniazid also delayed progression to HIV disease and AIDS and death. Thus isoniazid effectively decreases the incidence of tuberculosis and delays the onset of HIV-related disease in symptom-free HIV-seropositive individuals. Isoniazid prophylaxis should be considered for HIV-seropositive, PPD-positive subjects, and may also be appropriate for PPD-negative patients in areas where tuberculosis is highly endemic. A controlled and double-blind study to determine the efficacy of isoniazid in preventing the development of pulmonary tuberculosis among the household contacts of open cases of the disease has been carried out in a rural area of Kenya-a financially handicapped country-under realistic field conditions.A one-year course of isoniazid (5-10 mg per kg of body-weight in one daily dose) administered to the contacts of active cases gave a reduction in respect of the excretion of tubercle bacilli of the order of 90% at the end of the year. In the subsequent observation period (2-4 years) both the control and the isoniazid-treated group showed a low and similar rate of adverse findings.Previous studies by the Tuberculosis Chemotherapy and BCG Centre, Nairobi, had revealed that the risk of tuberculosis among household contacts, especially children, was high and, further, that the acceptability of the drug and the regularity of drug-taking were poor among these contacts. Even so, a very considerable prophylactic effect of isoniazid was demonstrated in the present study. It therefore seems justifiable to conclude that the treatment of household contacts with isoniazid could contribute to tuberculosis control in financially handicapped countries, particularly where a tuberculosis case-finding programme is reasonably well established. Patients with human immunodeficiency virus (HIV) infection and latent tuberculosis are at substantial risk for the development of active tuberculosis. As a public health measure, prophylactic treatment with isoniazid has been suggested for HIV-infected persons who have anergy and are in groups with a high prevalence of tuberculosis.
                We conducted a multicenter, randomized, double-blind, placebo-controlled trial of six months of prophylactic isoniazid treatment in HIV-infected patients with anergy who have risk factors for tuberculosis infection. The primary end point was culture-confirmed tuberculosis.
                The study was conducted from November 1991 through June 1996. Over 90 percent of the patients had two or more risk factors for tuberculosis infection, and nearly 75 percent of patients were from greater New York City. After a mean follow-up of 33 months, tuberculosis was diagnosed in only 6 of 257 patients in the placebo group and 3 of 260 patients in the isoniazid group (risk ratio, 0.48; 95 percent confidence interval, 0.12 to 1.91; P=0.30). There were no significant differences between the two groups with regard to death, death or the progression of HIV disease, or adverse events.
                Even in HIV-infected patients with anergy and multiple risk factors for latent tuberculosis infection, the rate of development of active tuberculosis is low. This finding does not support the use of isoniazid prophylaxis in high-risk patients with HIV infection and anergy unless they have been exposed to active tuberculosis. Tuberculosis (TB) preventive therapy is not effective in human immunodeficiency virus (HIV) infected adults with negative tuberculin skin tests (TSTs). However, there are insufficient data on patients with advanced HIV disease from high TB incidence areas.
                We conducted a randomised, double-blind, controlled trial comparing isoniazid (INH) with placebo among TST-negative adults with World Health Organization Stage 3 or 4 HIV disease. INH/placebo was administered for 12 months by patient-nominated supervisors. TST-positive participants were given open-label INH. Participants, who did not have access to antiretroviral therapy (ART), were followed up for 24 months with 6-monthly sputum culture and chest radiography.
                A total of 118 participants were enrolled: TST was negative in 98. In the randomised arms, the incidence of TB was 18/100 person-years (py) in the INH arm and 11.6/100 py in the placebo arm (hazard ratio 1.59, 95%CI 0.57-4.49). There were no significant differences in mortality, hospitalisation rate or CD4+ lymphocyte decline. INH/placebo adherence was 85%, and was significantly higher among participants with work-based treatment supervisors.
                We did not find any association between INH preventive therapy and reductions in incident TB among TST-negative adults with advanced HIV disease, but the study had limited statistical power. High levels of adherence were observed with patient-nominated supervisors. To determine the efficacy of isoniazid 300 mg daily for 6 months in the prevention of tuberculosis in HIV-1-infected adults and to determine whether tuberculosis preventive therapy prolongs survival in HIV-1-infected adults.
                Randomized, double-blind, placebo-controlled trial in Nairobi, Kenya.
                Six hundred and eighty-four HIV-1-infected adults.
                Development of tuberculosis and death.
                Three hundred and forty-two subjects received isoniazid and 342 received placebo. The median CD4 lymphocyte counts at enrolment were 322 and 346 x 10(6)/l in the isoniazid and placebo groups, respectively. The overall median follow-up from enrolment was 1.83 years (range, 0-3.4 years). The incidence of tuberculosis in the isoniazid group was 4.29 per 100 person-years (PY) of observation [95% confidence interval (CI) 2.78-6.33] and 3.86 per 100 PY of observation (95% CI, 2.45-5.79) in the placebo group, giving an adjusted rate ratio for isoniazid versus placebo of 0.92 (95% CI, 0.49-1.71). The adjusted rate ratio for tuberculosis for isoniazid versus placebo for tuberculin skin test (TST)-positive subjects was 0.60 (95% CI, 0.23-1.60) and for the TST-negative subjects, 1.23 (95% CI, 0.55-2.76). The overall adjusted mortality rate ratio for isoniazid versus placebo was 1.18 (95% CI, 0.79-1.75). Stratifying by TST reactivity gave an adjusted mortality rate ratio in those who were TST-positive of 0.33 (95% CI, 0.09-1.23) and for TST-negative subjects, 1.39 (95% CI, 0.90-2.12).
                Overall there was no statistically significant protective effect of daily isoniazid for 6 months in the prevention of tuberculosis. In the TST-positive subjects, where reactivation is likely to be the more important pathogenetic mechanism, there was some protection and some reduction in mortality, although this was not statistically significant. The small number of individuals in this subgroup made the power to detect a statistically significant difference in this subgroup low. Other influences that may have diluted the efficacy of isoniazid include a high rate of transmission of new infection and rapid progression to disease or insufficient duration of isoniazid in subjects with relatively advanced immunosuppression. The rate of drug resistance observed in subjects who received isoniazid and subsequently developed tuberculosis was low. As a result of numerous trials, isoniazid prophylaxis was shown to be effective in preventing tuberculosis in many different populations and under a variety of conditions. However, the duration of the protective effect has been of some concern. In a previous report, the protective effect of isoniazid prophylaxis among Alaskan Eskimos was shown to persist through the fifteenth year after its administration. In this final report, the protective effect is shown to persist for more than 19 years. The magnitude of the effect is related to the amount of isoniazid taken. The results of the study are consistent with the hypothesis that the decrease in risk of tuberculosis produced by isoniazid preventive therapy is lifelong. A randomized double-blind placebo-controlled trial was conducted to estimate the efficacy of preventive therapy for tuberculosis (TB) in HIV-infected adults in Lusaka, Zambia. The main outcome measures were the incidence of TB, mortality and adverse drug reactions.
                During a 2 year period, 1053 HIV-positive individuals without evidence of clinical TB were randomly assigned to receive 6 months of isoniazid twice a week (H), or 3 months of rifampicin twice a week (R) plus pyrazinamide (Z), or a placebo. Therapy was taken twice a week and was self administered. Subjects presenting with symptoms during the follow-up period were investigated for TB.
                The 1053 subjects in the study were followed up for a total of 1631 person-years (median = 1.8 years). Twenty-nine subjects were taken off treatment as a result of adverse drug reactions. A total of 96 cases of TB/probable TB (59 TB and 37 probable TB) were diagnosed during the study period and 185 deaths were reported. One hundred and fifteen subjects (11%) did not return to the study clinic at any time after enrolment. The incidence of TB was lower in those subjects on preventive therapy (H and RZ groups combined) compared with those on placebo (rate ratio = 0.60, 95% CI: 0.36-1.01, P = 0.057), as was the incidence of TB/probable TB (rate ratio = 0.60, 95% CI: 0.40-0.89, P = 0.013). The effect of preventive therapy was greater in those with a tuberculin skin test (TST) of 5 mm or greater, in those with a lymphocyte count of 2x10(9)/l or higher, and in those with haemoglobin of 10 g/dl or higher. There was no difference in mortality rates between the preventive therapy and placebo groups. The effect of preventive therapy declined after the first year of the study so that by 18 months the rates of TB in the treated groups were similar to that in the placebo group.
                This study has demonstrated that preventive therapy with either twice weekly isoniazid for 6 months or a combination of rifampicin and pyrazinamide for 3 months reduced the incidence of TB in HIV-infected persons in Zambia. No effect was observed on mortality. The effect was greatest in persons who had a positive TST or a lymphocyte count of 2x10(9)/l or greater, indicating that preventive therapy may be more effective in people with less advanced immunosuppression. The limited duration of the protective effect reported in this study raises the question of the need for lifelong preventive therapy or re-prophylaxis. Infection with the human immunodeficiency virus (HIV) greatly increases the risk of reactivation tuberculosis. We evaluated the safety and efficacy of three preventive-therapy regimens in a setting where exposure to tuberculosis is common.
                We performed a randomized, placebo-controlled trial in 2736 HIV-infected adults recruited in Kampala, Uganda. Subjects with positive tuberculin skin tests (induration, > or =5 mm) with purified protein derivative (PPD) were randomly assigned to one of four regimens: placebo (464 subjects), isoniazid daily for six months (536), isoniazid and rifampin daily for three months (556), or isoniazid, rifampin, and pyrazinamide daily for three months (462). Subjects with anergy (0 mm induration in reaction to PPD and candida antigens) were randomly assigned to receive either placebo (323 subjects) or six months of isoniazid (395). The medications were dispensed monthly and were self-administered.
                Among the PPD-positive subjects, the incidence of tuberculosis in the three groups that received preventive therapy was lower than the rate in the placebo group (P=0.002 by the log-rank test). The relative risk of tuberculosis with isoniazid alone, as compared with placebo, was 0.33 (95 percent confidence interval, 0.14 to 0.77); with isoniazid and rifampin, 0.40 (0.18 to 0.86); and with isoniazid, rifampin, and pyrazinamide, 0.51 (0.24 to 1.08). Among the subjects with anergy, the relative risk of tuberculosis was 0.83 (95 percent confidence interval, 0.34 to 2.04) with isoniazid as compared with placebo. Side effects were more common with the multidrug regimens, and particularly with the regimen containing pyrazinamide. Survival did not differ among the groups, but the subjects with anergy had a higher mortality rate than the PPD-positive subjects.
                A six-month course of isoniazid confers short-term protection against tuberculosis among PPD-positive, HIV-infected adults. Multidrug regimens with isoniazid and rifampin taken for three months also reduce the risk of tuberculosis.
Isoniazid prophylaxis in HIV-infected children has the potential to play a major public health role by reducing TB incidence and death. However there is as yet not enough data to guide the duration of prophylaxis, given empirically, nor to support its use in children on HAART and in those living in low TB prevalence areas, other than in situations of known TB contact. Further studies are needed to assess whether TB preventive therapy is of benefit in all HIV-infected children irrespective of use of antiretroviral treatment, the optimal duration of preventive therapy or long term benefits and adverse events.