Effectiveness of tuberculosis prophylaxis in patients with HIV/AIDS – retrospective analysis of data from Almaty, Kazakhstan, 2010–2015

Abstract

According to data from the National Centre for Prevention and Control of AIDS, in the Republic of Kazakhstan, 45.8% of patients in the symptomatic stages of HIV infection are diagnosed with tuberculosis (TB) which is the cause of death in 36% of patients infected with HIV. The aim of the study was to conduct a retrospective analysis of the effectiveness of tuberculosis (TB) chemoprophylaxis among people living with HIV in the Republic of Kazakhstan (RK) in Central Asia. Materials and method. A retrospective analysis of patient health status was performed for each of the 648 patients (323 in the study group and 325 in the control group) during 2010-2015. Data from outpatient treatment charts were used concerning each patient infected with HIV observed at AIDS Treatment Centres. From among the 648 patients infected with HIV, 136 were receiving isoniazid in 2010, and 187 in 2011. The control group consisted of 325 people living with HIV (PLW HIV), who did not received isoniazid during observation. Results. The incidence of TB in patients who underwent chemoprophylaxis did not exceed 0.555/ 100,000 population in the first year of observation. Within 5 years, the TB incidence dropped to 0. In the control group, the TB incidence rate during the first year of observation was 3.262/100,000, with a decrease to 0.364 observed in 2015. Cumulated incidence rate in 2011-2015 in the study group accounted for 1.276/100,000. In the control group, the cumulative incidence was 4.3 times higher and accounted for 5.527. A significant difference in the mortality rate due to TB in the study and control groups was observed, the share of deaths due to TB in study group was 21.6% - nearly 3 times lower than in the control group (57.0%). Conclusions. The effectiveness of chemoprophylaxis for TB depends on biomedical, organizational and cultural factors. The presence of HIV co-infections is a special situation. Opposite to the majority of reports, in own study, no drug-resistant forms of tuberculosis were observed in relation with chemoprophylaxis with isoniazid. In the examined population, TB chemoprophylaxis reduced the incidence and cumulative incidence of TB among PLW HIV by 3.4-4.8 times. Isoniazid chemoprophylaxis decreased 4-fold the annual and cumulative mortality due to TB.