HIV-Positive Individuals May Benefit from Long-Term TB Drug Isoniazid
The tuberculosis drug isoniazid may help prevent recurrent bouts of the disease among HIV-positive individuals, according to new research published in this week's Lancet. Researchers from Cornell University Medical College performed a randomized trial in Port Au Prince, Haiti, "to determine whether recurrent tuberculosis after curative TB treatment is more common in HIV-infected individuals than [uninfected] individuals, and to determine whether post-treatment isoniazid prophylaxis decreases the risk of recurrent tuberculosis." The study followed 233 TB patients, 142 of whom were HIV-positive. After receiving a basic six-month rifampicin-containing regimen for active pulmonary TB, 68 HIV-positive patients were assigned follow-up isoniazid treatment, while 74 were placed on a placebo. In addition, 51 HIV-negative TB patients were assigned to the isoniazid group and 40 to the placebo group (Fitzgerald et al., Lancet, 10/28). Among all patients taking the placebo, HIV-infected patients were more than 10 times as likely to experience a TB relapse than HIV-negative patients. However, HIV-positive patients taking isoniazid were significantly less likely to have a TB relapse than HIV-positive patients taking the placebo. The recurrence rate for TB among HIV-positive patients taking isoniazid was 1.4 infections per 100 HIV-infected people per year, compared to 7.8 among HIV-positive patients taking the placebo. According to Dr. Daniel Fitzgerald, study co-author, this study reveals that a six-month course of the drug rifampicin followed by a year of isoniazid "effectively decreases the risk of recurrent tuberculosis in this population." Study authors added that while TB recurrence is not associated with increased death rates, such relapses are costly "and have the potential to stretch already limited resources in developing countries where both HIV and TB are epidemic" (Reuters Health, 10/27). A second tuberculosis-related study published in this week's Lancet emphasizes the importance of HIV testing among TB patients. Researchers led by Dr. E. Frances Bowen of St. George's Hospital in London, taking prospective blood samples from TB patients at three London clinics, found that the number of TB patients who were also infected with HIV has increased over time: about 11% of 202 TB patients were HIV positive, or more than double the 1993 and 1998 estimated rates. Authors conclude that this trend will have implications for an "already overstretched" health care system (Bowen et. al., Lancet, 10/28).This is part of the KHN Morning Briefing, a summary of health policy coverage from major news organizations. Sign up for an email subscription.