The Effect of Long-Term HAART on the Incidence of Tuberculosis Among People Living with HIV in Addis Ababa, Ethiopia: A Matched Nested Case-Control Study.

Background: The introduction of antiretroviral therapy (ART) significantly decreases the incidence of tuberculosis (TB) in people living with human immunodeficiency virus (PLWHIV). However, a considerable proportion is still co-infected with TB after ART initiation. Thus, this study aimed to assess the effect of long-term HAART on the incidence of TB among PLWHIV in Addis Ababa, Ethiopia.

Methods: A matched nested case-control study was conducted among PLWHIV who were enrolled in ART clinics in Addis Ababa, Ethiopia from 2013 up to 2018. Cases were HIV-TB co-infected individuals who were taking antiretroviral treatment, while controls were PLWHIV without TB who were taking antiretroviral treatment. The cases and controls are matched exactly in age and sex. Data were entered in Epi Info version 7.1 and analyzed using SPSS version 20. Bi-variable and multivariable conditional logistic regression were employed along with 95% CI. A P-value <0.05 in the multivariable analysis was considered statistically significant.

Results: Fifty-seven cases were compared with 114 controls. Accordingly, previous TB history (X; 13.790, < 0.001), baseline functional status (X; 9.120, = 0.010), baseline WHO clinical stage (X; 10.083, = 0.001), baseline hemoglobin value (X; 6.985, = 0.008), baseline body mass index (X; 3.873, = 0.049), isoniazid preventive treatment (X; 8.047, = 0.005), baseline CD4 value (X; 12.741, < 0.001) and length of stay on ART (X; 53.359, < 0.001) were associated with developing TB. Length of stay on ART was found to be the statistically significant determinant of TB infection after ART initiation (aOR = 5.925, 95% CI = 2.649-13.250).

Conclusion: Advanced clinical stages at the baseline, previous TB history, and not taking IPT were associated with TB infection. The long-term ART exposure significantly decreases tuberculosis incidence in PLWHIV. Thus, retaining PLWHIV on ART would be important to decrease the incidence of TB in this group of individuals.