Steep Fall in Incidence of TB Among HIV-Positive Heterosexuals in the UK

Investigators in the United Kingdom (UK) studied three national databases to determine the incidence of TB among HIV-infected heterosexuals living in England and Wales from 2002 to 2010. Results based on these databases show that, throughout this time period, incidence of TB decreased from 30 per 100 individuals to 8.8 per 1,000 individuals. The databases indicated that 45,322 heterosexuals received treatment for HIV infection in England and Wales; 4,266 of these individuals also were diagnosed with active TB. More than half of the individuals (54 percent) received an initial simultaneous diagnosis of HIV and TB, while 38 percent were diagnosed with TB more than three months after their HIV diagnosis. Almost all of the simultaneous diagnosis patients (92 percent) were diagnosed late with HIV and 53 percent had a CD4 cell count lower than 100 cells per cubic millimeter.

According to the investigators, this decrease is due both to a fall in the number of TB diagnoses and an increase in the total number of heterosexual adults living with HIV. Also, the investigators believe that patients are becoming less susceptible to TB. There was a drop in the number of heterosexuals in the United Kingdom acquiring HIV in sub-Saharan Africa, where there is a high prevalence of TB. Approximately 84 percent of the patients diagnosed with TB were black Africans.

Factors associated with TB coinfection included gender (male versus female), ethnicity (black African, Indian, Pakistani, or Bangladeshi), and acquiring HIV abroad. Also, the use of antiretroviral therapy (ART) among persons with a CD4 cell count less than 350 cells per cubic millimeter increased in response to national HIV treatment guidelines.

The TB incidence among HIV-infected heterosexuals was significantly higher than in the general UK population (0.14 per 1,000 individuals). Incidence of TB among HIV-infected black Africans (11 per 1,000 individuals) was approximately four times higher than the UK rate for HIV-negative Africans born abroad (2.7 per 1,000 individuals) and 25 times higher than the rate among HIV-negative black Africans born in the UK (0.43 per 1,000 individuals). The incidence of TB among HIV-positive persons not taking ART was more than 14 times higher than those on ART (56 per 1,000 individuals versus 3.9 per 1,000 individuals). The highest TB incidence for the study period was among persons not taking ART, who had a CD4 cell count below 200 cells per cubic millimeter .

The study, "Decreasing Incidence of Tuberculosis Among Heterosexuals Living with Diagnosed HIV in England and Wales," was published online in the journal AIDS (doi: 10.1097/QAD.0b013e32835e2cb1).

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