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Preventive therapy using the antibiotic isoniazid significantly reduces the incidence of tuberculosis and death when widely used in public HIV clinics, an international effort led by physician-scientists at Rio de Janeiro Municipal Health Secretariat, Brazil, and the Johns Hopkins University in the United States, and funded by The Consortium to Respond Effectively to the AIDS/TB Epidemic (CREATE) reported.
The benefits of isoniazid preventive therapy, or IPT, are most pronounced in those HIV patients who receive regular care. The THRio study (TB and HIV in Rio), led by Dr Betina Durovni, of the Rio de Janeiro Municipal Health Secretariat, studied 29 clinics in the city of Rio de Janeiro, Brazil, including almost 13,000 HIV-positive patients, to determine the impact of IPT on rates of TB and death in the HIV-positive population using the Brazilian public health system. The Brazilian Ministry of Health recommends the use of IPT in people living with HIV, but the policy had been poorly implemented nationwide. The THRio study promoted more aggressive use of IPT by training clinic staff in the importance of preventing TB in people living with HIV and by teaching doctors and nurses how to perform TB testing.
Phased implementation
The investigators used a "phased implementation" design for the intervention study, meaning that clinics received training in the use of IPT in a sequential fashion, with all clinics eventually being included. Rates of TB were compared in clinics before and after the intervention.
According to the results presented at the International AIDS Society’s 6th International Conference on HIV Pathogenesis, Treatment and Prevention in Rome, Italy, on 20 July, a 13% reduction in TB incidence and a 28% reduction in TB or death were found in the study clinics following the introduction of routine use of IPT. In analyses that included only those patients receiving regular care, a 43% reduction in TB and a 44% reduction in TB or death were found. Previous work from the THRio study had shown that IPT was highly effective at the individual level, but the new results also demonstrate a population-level benefit (The impact of antiretroviral therapy and isoniazid preventive therapy on tuberculosis incidence in HIV-infected patients in Rio de Janeiro, Brazil. Golub JE, Saraceni V, Cavalcante SC, et al. AIDS. 2007;21(11):1441-8.)
Real-world scenario
"The THRio study results show a reduction in TB and death among our HIV patients in a 'real world' scenario rather than in a more structured clinical trial, even with the many obstacles faced when implementing this important intervention," says Durovni. "For individuals living with HIV, IPT is an effective prevention tool that benefits the entire community, not just individual patients," she adds.
The authors report that following the intervention, rates of TB testing increased dramatically and a high proportion of patients went on to be treated with IPT. Adherence to IPT was unusually high in this community setting, with more than 80% of patients started on IPT completing the full 6-month course of treatment. In the US, almost half of patients started on IPT never complete the treatment according to some studies.
Challenges
The results presented also emphasize a number of challenges in combating HIV-related TB. Patients in the THRio study were given IPT if they had a positive skin test for TB, but more than one-third of TB cases in the study occurred before the test could be performed. Better and simpler diagnostic tests for TB infection are a high priority, according to Durovni. In addition, a large number of TB cases occur before patients are diagnosed with HIV infection, underscoring the importance of earlier detection of HIV in the community.
"THRio has provided us with valuable insights and implications for new research directions. Our results highlight the importance of fully funding research on better tools and strategies to fight TB in communities with high HIV prevalence," says Jonathan Golub, Ph.D., M.P.H., co-investigator of the THRio study. "TB remains the leading cause of death in people with HIV, and the current efforts for preventing TB globally are not sufficient. THRio emphasized preventing TB among HIV clinic patients, and national TB and HIV/Aids programmes need to continue to develop integrated approaches to ensure HIV infected patients receive appropriate and necessary TB screening and care if we are to have a significant impact on these convergent epidemics. - (Health24, July 2011)
- Press release issued by CREATE
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