Liver fibrosis in HIV-infected individuals on long-term antiretroviral therapy: associated with immune activation, immunodeficiency and prior use of didanosine.

BACKGROUND: It is unclear whether HIV infection is associated with liver fibrosis in the absence of chronic hepatitis B or C virus (HBV/HCV) coinfection. We compared prevalence of liver fibrosis, noninvasively assessed by the Fibrosis-4 (FIB-4) index, between HIV-infected patients and uninfected controls, and explored determinants of a higher FIB-4 score, indicative of more liver fibrosis.
METHODS: FIB-4 was assessed in HIV-uninfected and HIV-1-infected, predominantly virologically suppressed participants of the AGEhIV Cohort Study without HBV and/or HCV coinfection, and aged at least 45. Using multivariable regression, we investigated associations between FIB-4 and HIV-status, HIV-disease characteristics, antiretroviral drugs and markers of microbial translocation and immune activation.
RESULTS: Prevalence of advanced liver fibrosis (FIB-4 ≥ 3.25) was low: 1.4% in HIV-infected and 1.0% in HIV-uninfected participants. After adjustment for age, sex, ethnicity, detectable anti-hepatitis B core/anti-HCV antibodies and excessive alcohol intake, HIV remained significantly associated with higher FIB-4 (+4.2%, P = 0.05). Prior exposure to didanosine, longer duration of a CD4 cell count below 500 cells/μl and a lower CD4 cell count at enrollment were each associated with a higher FIB-4. Markers of immune activation (soluble CD163, activated CD8 T-lymphocytes and regulatory T-lymphocytes) were associated with a higher FIB-4 in HIV-infected but not HIV-uninfected study participants.
CONCLUSION: HIV infection was independently associated with higher FIB-4 scores, indicating more advanced liver fibrosis, though the difference in FIB-4 scores between HIV-infected and HIV-uninfected was small. Higher levels of immune activation were associated with liver fibrosis in HIV-infected, even in the absence of HBV or HCV infection, but not in HIV-uninfected individuals.