Injecting drug use predicts active tuberculosis in a national cohort of people living with HIV.

objectivesTuberculosis (TB) is common in people living with HIV, leading to worse clinical outcomes including increased mortality. We investigated risk factors for developing TB following HIV diagnosis.

designAdults aged at least 15 years first presenting to health services for HIV care in England, Wales or Northern Ireland from 2000 to 2014 were identified from national HIV surveillance data and linked to TB surveillance data.

methodsWe calculated incidence rates for TB occurring more than 91 days after HIV diagnosis and investigated risk factors using multivariable Poisson regression.

resultsA total of 95 003 adults diagnosed with HIV were followed for 635 591 person-years; overall incidence of TB was 344 per 100 000 person-years (95% confidence interval 330-359). TB incidence was high for people who acquired HIV through injecting drugs [PWID; men 876 (696-1104), women 605 (365-945)] and black Africans born in high TB incidence countries [644 (612-677)]. The adjusted incidence rate ratio for TB amongst PWID was 4.79 (3.35-6.85) for men and 6.18 (3.49-10.93) for women, compared with MSM. The adjusted incidence rate ratio for TB in black Africans from high-TB countries was 4.27 (3.42-5.33), compared with white UK-born individuals. Lower time-updated CD4 cell count was associated with increased rates of TB.

conclusionPWID had the greatest risk of TB; incidence rates were comparable with those in black Africans from high TB incidence countries. Most TB cases in PWID were UK-born, and likely acquired TB through transmission within the United Kingdom. Earlier HIV diagnosis and quicker initiation of antiretroviral therapy should reduce TB incidence in these populations.