Isoniazid Preventive Therapy Uptake and Its Effect on Tuberculosis Incidence Among People Living with HIV in Illubabor and Buno Bedelle Zones, South-West Ethiopia, 2022: A Retrospective Cohort Study.

Introduction: Tuberculosis (TB) remains the leading cause of death among human immune deficiency virus (HIV) patients. Based on the 2020 global TB report, Ethiopia was among the 30 high TB and TB/HIV burden countries. This study filled gaps regarding IPT uptake in the study area and representative sample determination for assessing TB incidence and its predictors at public health facilities in Illubabor and Buno Bedelle zones, south-west Ethiopia.

Methods: This retrospective cohort study was conducted among people living with HIV (PLHIV) who were on antiretroviral therapy (ART) at public health facilities in Illubabor and Buno Bedelle zones, south-west Ethiopia. Both isoniazid preventive therapy (IPT) exposed and unexposed PLHIV were followed from the date of ART initiation until the date of TB diagnosis of the most recent visit prior to the end of follow-up. The Cox proportional hazard model was employed to identify variables that predicted the incidence of TB at a P value of <0.05.

Results: Data were collected on 421 PLHIV, with a response rate of 97.4%. The median (interquartile range (IQR)) age of the study participants was 32 (28-40) year. The incidence rate of pulmonary TB was 3.1 per 1000 person-months (95% CI: 2.4-3.9). The incidence rate of TB among IPT-exposed PLHIV was 1.45 per 1000 person-months, but it was 6.2 per 1000 person-months in the unexposed group. Patient's residence, IPT exposure, baseline ART adherence, baseline hemoglobin level, baseline CD4+ cell, recent hemoglobin level, recent CD4+ cell, recent BMI, and recent WHO HIV clinical stage were independently associated with the incidence of TB.

Conclusion: Healthcare professionals working in ART clinics should routinely assess HIV-positive individuals for changes in clinical indicators and environmental exposures like living conditions, which will help HIV-positive individuals in reducing their risk for TB. Likewise, patients attending ART clinics should receive counseling on a regular basis.