Incidence Rate of Tuberculosis Among Individuals With HIV in Africa Higher Than Estimated

Individuals living in sub-Saharan Africa with HIV had a higher incidence rate of tuberculosis (TB) than had previously been estimated by the World Health Organization (WHO) 2022 Africa regional estimated report, according to a systematic review and meta-analysis published in BMC Infectious Diseases.

TB is the leading cause of death in patients with AIDS. HIV infection is the strongest risk factor for infection with Mycobacterium tuberculosis, which caused TB. Sub-Saharan Africa accounts for 75% of the global HIV/AIDS prevalence, and in its 2021 global TB report, the WHO estimated that Africa had TB incidence rates of 212 total and 42 HIV-positive TB cases per 100,000 population. This review aimed to “determine new [TB] occurrences, which indicate current disease transmission, as well as contributing factors that can be used to develop TB control programs at the community and regional levels.”

Diagnosis - Tuberculosis. Medical Concept. | Image credit: tashatuvango - stock.adobe.com

The authors used PubMed, CINHAL, Google Scholar, online journals based in Africa, and Google to search for studies. Studies that were published between January 1, 2000, and November 25, 2022, and included TB incidence rates in people with HIV living in sub-Saharan Africa were included in the review. The dependent variable of the review was the incidence of TB in patients living with HIV.

There were 43 studies from 13 sub-Saharan countries that were included in the review; East Africa had Africa had 27 studiesies,studies, West Africa had 7 studies,, and Central Africa had only 1 study. Ethiopia, Uganda, and Tanzania were the most frequently studied countries. The majority of the studies included were retrospective and prospective cohort studies. Most of the studies were conducted on adults, with only 9 of the 43 studies conducted on children and adults. There were 854,083 patients with HIV included in this review overall, with TB detected in 38,752 of them.

The pooled incidence rate of TB per 100 person-years in patients infected with HIV was 3.49 (95% CI, 2.88-4.17), with significant heterogeneity. Central Africa was found to have the highest incidence rate of TB in people living with HIV/AIDS (7.70; 95% CI, 6.39-9.24), with no heterogeneity. This was followed by South Africa (3.96; 95% CI, 2.43-5.85), which had high heterogeneity, and West Africa had the lowest incidence rate (1.82; 95% CI, 1.02-2.83).

Prospective cohort studies (3.81; 95% CI, 2.9-4.84) and retrospective studies (3.43; 95% CI, 2.73-4.2) both revealed a high incidence rate of TB. Studies with follow-up periods of 5 years or more showed an incidence rate of 3.62 (95% CI, 2.41-5.08) whereas those with follow-up periods shorter than 5 years had an incidence rate of 3.23 (95% CI, 2.62-3.91).

Risk factors in the incidence of TB in patients with HIV included being underweight, having anemia, being male, having low CD4 counts, being bedridden, lacking isoniazid prevention therapy, lacking cotrimoxazole, and being in advanced WHO clinical stages of HIV. Patients with HIV who were underweight were 1.79 times more likely to have TB compared with HIV patients who were of normal weight (adjusted HR [aHR], 1.79; 95% CI, 1.61-1.96). Low levels of CD4 were also a risk factor for TB (aHR, 1.23; 95% CI, 1.1-1.35). Patients who were in WHO clinical stages 3 and 4 of HIV were also more likely to develop TB compared with those in WHO clinical stages 1 and 2 (aHR, 2.29; 95% CI, 1.34-3.23). Lastly, patients with HIV who also have anemia were more likely to develop TB compared with nonanemic patients (aHR, 1.73; 95% CI, 1.34-2.13).

There were some limitations to this study. Data from retrospective cohort studies could be incomplete and only factor in limited variables. Some studies had a limited follow-up time. There was significant heterogeneity in the incidence rates of TB in subgroup analyses that could not be fully explained.

The researchers concluded that their study’s incidence rate of TB was higher than that estimated in the WHO’s 2022 report. They wrote that donor countries and institutions such as WHO should be involved in focusing on dual infection testing and treatment.

Reference

Wondemeneh TG, Mekonnen AT. The incidence rate of tuberculosis and its associated factors among HIV-positive persons in sub-Saharan Africa: a systematic review and meta-analysis. BMC Infect Dis. 2023;23:613. doi:10.1186/s12879-023-08533-0