The annual rate of tuberculosis (TB) cases among people infected with HIV is over 40 times greater than case rates among the general population of the United States, according to new data from the Centers for Disease Control and Prevention (CDC). The findings, presented by CDC researchers at the 12th World AIDS Conference, underscore the critical need for greater TB screening and prevention efforts among people who are HIV-positive. Because HIV infection severely weakens the immune system, people with HIV are at greater risk of also developing TB disease.
Worldwide, TB remains the leading cause of death among people who are infected with HIV," said Helene Gayle, M.D., M.P.H., Director of CDC's National Center for HIV, STD, and TB Prevention. "We know the toll of these interconnected epidemics. We now need to strengthen our prevention efforts to include TB screening for all people infected with HIV and, if needed, preventive therapy to avoid developing TB disease."
CDC researcher, Diane Bennett, M.D., examined the rate of TB in HIV-infected and uninfected populations in the U.S. between 1993 and 1996 and found an extremely high rate of TB among HIV infected individuals (333 per 100,000) compared to the general population. She also finds that African Americans are disproportionately impacted by both epidemics, with three times as many African Americans diagnosed with TB and AIDS as whites.
Bennett also profiles the intersection between HIV and TB in the United Kingdom, and finds rates of TB among HIV-infected populations that are 116 times the rates of TB in the general population. Because HIV prevalence is much lower in the U.K., many individuals with both diseases have immigrated to the U.K. from nations more heavily impacted by AIDS. "Clearly TB continues to have a dramatic impact on HIV-infected individuals across the globe, and international collaboration will be essential to combat both epidemics," said Bennett.
In a related poster presentation, CDC researcher Mary Reichler, M.D., examines the implications of HIV infection, not only for TB prevention, but also for the proper diagnosis and treatment of active disease. Reichler examines the occurrence of pulmonary and extrapulmonary TB among individuals who were HIV positive, compared to uninfected individuals, and finds very different patterns of disease manifestation. Extrapulmonary TB occurs when the disease spreads to areas outside the lungs, most frequently the lymph nodes.
Findings indicate that HIV-positive individuals are much more likely to have both extrapulmonary and pulmonary TB than uninfected individuals. Moreover, the sites of disease outside the lungs varied greatly for HIV-infected individuals compared with uninfected individuals.
Extrapulmonary TB patients with HIV were also more likely to have drug-resistant strains of TB. These findings underscore the critical need for physicians treating TB disease to learn the HIV status of their patients and understand the implications for treatment.