HIV and Tuberculosis: A Potentially Deadly Combination

For people living with HIV, the risk of contracting tuberculosis (TB) is significantly elevated—up to 16 to 27 times greater than in people who don’t have HIV, according to the World Health Organization. It’s a major cause of mortality in the HIV-positive population worldwide, with 370,000 deaths attributed to TB in 2016. Results of a recent study of HIV-positive patients in South Africa and Malawi demonstrated that even after quick diagnosis of TB, the death rate for this population remains high.

A team of investigators at the London School of Hygiene & Tropical Medicine; University of Malawi College of Medicine; University of the Witwatersrand in Johannesburg; University of KwaZulu-Natal in Pietermaritzburg; Liverpool School of Tropical Medicine, and Dignitas International set out to discover the factors associated with mortality in HIV-positive people with TB, as well as how frequently disseminated TB kills and how antiretroviral therapy (ART) may play a role in mortality. This study was part of the larger STAMP trial, which examined the effects of rapid urine-based TB screening of HIV-positive patients in South Africa and Malawi. Findings were published in Clinical Infectious Diseases.

The latest study (the STAMP study subset) included 322 patients admitted to hospitals who were living with HIV and had been diagnosed with TB. Although more than four-fifths of subjects who knew they were HIV positive were on an ART regimen at the time of admission, their CD4 cell counts were very low, with a median of 75 cells/uL (below the threshold of 200 cells/uL that signifies AIDS). Even in the patients who had been taking ART for at least 6 months, the median CD4 cell count was just 96 cells/uL. Viral loads in patients who had been on ART for 6 months or less revealed that nearly half were virally unsuppressed despite medication.

The result? The mortality rate for patients in this study was 30.7%, measured 56 days after diagnosis—although a significant number of subjects died within a week of hospital admission.

According to the study’s authors, it’s important to find ways to reduce the risk of TB developing in HIV-positive people.

“This involves early HIV diagnosis through regular testing, and early initiation of ART to prevent significant immunosuppression—having advanced disease will increase [the] risk of TB disease and [the] risk of dying if TB disease develops,” Ankur Gupta-Wright, PhD, a specialty registrar in infectious diseases and general (internal) medicine and a clinical research fellow at the London School of Hygiene & Tropical Medicine, and an author of the study, told Contagion®.

“The failure of ART, either due to people not taking ART [as prescribed] or drug resistance, plays an important role in developing TB and TB mortality, as these patients will present with more advanced disease,” said Dr. Gupta-Wright. “Patients newly starting ART with (undiagnosed) TB are also at higher risk of death, suggesting we need to be better at screening for TB when starting ART.”

Also important is follow-up care, he noted, as many people with TB and HIV die after being released from the hospital.

Men in this study had a higher rate of mortality (36.8%) compared with women (23.8%), the reasons for which Dr. Gupta-Wright said are not clear. He suggested that men might drag their feet compared with women when it comes to seeking medical care, either in general or in the case of HIV and TB specifically. “There may be social and/or biological reasons men are more likely to develop TB and die after developing TB,” he said. “Men are a vulnerable and neglected population in this setting.”