Determinants of HIV-1 virologic suppression in HIV-associated tuberculosis in Brazil

Tuberculosis/human immunodeficiency virus (TB/HIV) coinfection is associated with advanced HIV disease and variable responses to antiretroviral therapy (ART).

We examined whether baseline HIV severity markers, ART regimes, or human genetic variants influenced HIV-1 virologic suppression in HIV-associated TB.

We included TB/HIV participants from Regional Prospective Observational Research in Tuberculosis (RePORT)-Brazil study, who received standard TB therapy and antiretroviral treatment. The primary endpoint was HIV-1 virologic suppression (≤ 1,000 copies/mL); Baseline characteristics, viral load (VL), CD4 cell count, timing of ART initiation, and ART regimens were included. We genotyped UGT1A1 (rs887829; integrase strand transfer inhibitor-related) and CYP2B6 [rs3745274, rs28399499, rs4803419; efavirenz (EFZ)-related]; all have defined normal, intermediate, and slow genotypes. Genotyping was performed by MassARRAY iPLEX Gold; Kaplan-Meier curves compared time-to-suppression with log-rank tests; Cox proportional hazards models estimated hazard ratios.

Among 194 participants, 68% (n = 132) achieved virologic suppression (≤ 1,000 copies/mL). Median time-to-suppression: 84 days [95% confidence interval (CI): 42-125]. Participants with higher baseline viral load (BVL) (≥ 5 log10 copies/mL) had delayed suppression compared with those with lower VL (< 5 log10; log-rank χ² = 75.9; p < 0.001). Individuals with CD4 ≤ 200 cells/µL suppressed more slowly than those with CD4 > 200 cells/µL (log-rank χ² = 29.6; p < 0.001). Participants starting ART before TB treatment achieved suppression faster than ART-naïve individuals (32 vs. 147 days; log-rank χ² = 48.5; p < 0.001). Higher BVL was associated with reduced hazard of suppression [adjusted hazard ratio (aHR) = 0.67; 95% CI: 0.61-0.75], while higher baseline CD4 count increased the hazard of suppression (per 100 cells/µL: aHR = 1.11; 95% CI: 1.01-1.21). ART-naïve status was associated with lower hazard of suppression in univariate analysis (Hazard Ratio = 0.51; 95% CI: 0.36-0.72) but not after adjustment. ART regimen class and pharmacogenetic metabolizer profiles were not significantly associated with virologic suppression.

BVL and CD4 count were the strongest determinants of virologic suppression in TB/HIV patients. Suppression rates were low, and neither ART regimen nor pharmacogenetic profiles significantly influenced the likelihood of suppression.