Assessment of the spread of tuberculosis infection among patients with HIV infection who were under the observation of phthisiatricians in the city of Moscow

The aim of the study was to study the prevalence of latent tuberculosis infection (LTBI) and the incidence of active forms of tuberculosis (TB) depending on the implementation of preventive therapy for tuberculosis (PT) in patients with HIV infection. Materials and methods . As part of a retrospective analysis of the registry information of regional TB surveillance system, the data of 33,414 patients with HIV infection who first visited a tTB doctor in 2016–2023 were studied. The observation period ranged from 1 to 8 years. In 2016–2023, 745 cases of tuberculosis were identified among patients. To solve the research aims, three samples were made. An assessment of the characteristics of patients who visited a tuberculosis specialist in 2016–2023 was carried out based on the data of 31,614 patients with HIV infection who were not TB diagnosed or suspected of having tuberculosis during the initial screening and who were not registered with a TB institution as a patient with active forms of the disease. To assess the detection of LTBI during the first visit to the office, an analysis of data from 25,848 patients was performed, in whom tuberculosis was not detected during the first visit registered in 2016–2023, and the immunological test results using the recombinant tuberculosis allergen were known. Among 24,581 patients from the above-mentioned persons, in whom LTBI was not detected during the first visit to the office, an assessment of LTBI detection was performed during repeat visits to a TB specialist. To analyze the incidence of tuberculosis depending on the implementation of preventive therapy (PT) in 2017–2023, data from 30,195 patients who first visited a TB specialist in 2016–2022 and who had no TB history either before the first visit or during the first three months after the first visit were reviewed. The annual incidence of tuberculosis was compared in patients who did not receive PT, with a one-year observation period 90 days after the first visit to a TB doctor; and in those who received PT, with a one-year observation period 6 months after the start of the PT course. Results and discussion . In 2016–2023, the proportion of people with LTBI at the first visit to a doctor fluctuated between 3.4% (in the «covid» year of the COVID-19 pandemic) to 5.2%, with an average value of 4.6% (95% CI: 4.3–4.8%). During repeat visits to a doctor, LTBI was detected annually in 2.2–2.8% of people. Comparison of the annual incidence of tuberculosis in two groups: those who did not receive and those who received preventive therapy showed that preventive therapy against tuberculosis reduces the chance of developing tuberculosis by almost half (OR=1.9, 95% CI: 1.2–2.9). For people who did not receive antiretroviral therapy, the chance of developing tuberculosis decreases by 3.5 times (OR=3.5, 95% CI: 1.3–9.4). In patients with CD4+ lymphocyte levels less than 350 cells/ml, the probability of developing the disease decreased by 3.5 times (OR=3.5, 95% CI: 2.0–6.1). In patients with HIV/LTBI, in the absence of a full course of preventive therapy for tuberculosis, the chance of developing tuberculosis increased more than 4 times (OR=4.2, 95% CI: 1.5–11.7). Conclusion : Using a large data set of HIV-infected patients visiting a TB specialist, the prevalence of LTBI was assessed and statistically significant effectiveness of PT was demonstrated, especially in patients with low CD4+ levels and LTBI.