Higher risk of mortality in HIV-HBV co-infected patients from sub-Saharan Africa is observed at lower CD4⁺ cell counts

BACKGROUND: Hepatitis B virus (HBV) co-infection in human immunodeficiency virus (HIV)-positive individuals increases the risk of overall mortality, especially when HBV DNA levels are high. The role of CD4+ cell counts in this association is poorly defined. We aimed to determine whether HIV-HBV co-infection influences changes in CD4+ cell count before and during antiretroviral therapy and whether it affects mortality risk at levels of CD4+. METHODS: 2052 HIV-positive participants from Côte d'Ivoire in a randomized-control trial assessing early or deferred ART were included. HBV-status was determined by hepatitis B surface antigen (HBsAg). Changes in CD4+ cell levels were estimated using a mixed-effect linear model. The incidence rates of all-cause mortality were estimated at CD4+ counts ≤350, 351-500, >500/mm3 and were compared between HBV-status groups as incidence rate ratios (IRR). RESULTS: At baseline, 190 (9%) were HBsAg-positive [135 (71%) with HBV DNA <2000 IU/mL, 55 (29%) ≥2000 IU/mL]. Follow-up was a median 58 months (IQR = 40-69). Between co-infection groups, there were no differences in CD4+ decline before ART initiation and no differences in CD4+ increase after ART initiation. After adjusting for sex, age, baseline HIV RNA level, and early/deferred ART arm, mortality rates were not significantly different between HBsAg-positive versus HBsAg-negative participants across strata of CD4+ levels. However, HBsAg-positive individuals with HBV-DNA ≥2000 IU/mL versus HBsAg-negative individuals had increased mortality rates at ≤350/mm3 (adjusted-IRR = 3.82, 95% CI = 1.11-9.70) and 351-500/mm3 (adjusted-IRR = 4.37, 95% CI = 0.98-13.02), but not >500/mm3 (adjusted-IRR = 1.07, 95% CI = 0.01-4.91). CONCLUSION: Despite no effect of HBV-infection on CD4+ levels, HIV-HBV co-infected individuals with high HBV replication are at higher risk of mortality when CD4+ is <500/mm3.