Abstract / Summary
Background: Global reports of tuberculosis (TB) in 2024 estimated 10.7 million cases, of which 5.8% were HIV-positive individuals. Despite the implementation of TB preventive therapy, TB incidence rates remain high, especially among HIV-infected patients.
Methods: A retrospective cohort study was conducted from 1 October 2020 to 31 October 2025. A two-stage sampling procedure was used to select both health facilities and study participants. First, seven public health facilities in the West Arsi zone were selected using simple random sampling. Second, 426 people living with HIV were randomly selected from ART registers of the selected health facilities. The data were collected via the Kobo Toolbox and analysed via SPSS Version 26. Kaplan‒Meier estimates were used for time‒event distribution; for survival, curves were compared via log-rank tests. Risk factors for active TB were identified through Cox proportional hazards regression, with significance at p < 0.05.
Results: A total of 426 HIV-positive patients were followed for 1867 person-years, during which 71 individuals (16.7% of participants) developed TB, resulting in a TB incidence density rate of 3.78 per 100 person-years. The identified risk factors for developing active TB were WHO Clinical Stages II to IV (adjusted hazard ratios [AHR] = 3.44 [95% CI: 1.50-7.85], 5.41 [95% CI: 2.47-11.84] and 7.52 [95% CI: 3.09-18.32], respectively). Participants who received daily isoniazid for 6 months (INH/6H) and those who did not receive any TPT regimen had significantly greater hazard of developing TB compared to those receiving 3HP (AHR = 5.01, 95% CI: 2.35-10.65 and AHR = 12.53, 95% CI: 5.65-27.79, respectively). Similarly, individuals with haemoglobin (HBg) levels < 11 g/dL had a markedly increased risk of TB (AHR = 2.46, 95% CI: 1.31, 4.60), as did those with a body mass index < 18.5 kg/m2 (AHR = 4.37, 95% CI: 2.14, 8.95).
Conclusion: This study revealed that 16.7% of participants developed active TB. Significant risk factors for TB incidence among HIV-positive individuals were identified, highlighting the need for targeted preventive strategies to address these risks, particularly in high-risk populations.