Hepatitis C virus co-infection increases neurocognitive impairment severity and risk of death in treated HIV/AIDS.

Previous studies have reported that hepatitis C virus (HCV) co-infection worsens neurocognitive status among individuals with human immunodeficiency virus (HIV)-1 infection. We assessed the prevalence of neurologic disorders and the severity of HIV-associated neurocognitive impairment among HIV-infected individuals in two centralized HIV clinics in Alberta, Canada from 1998 to 2010 based on their HCV serostatus. Of 456 HIV-infected persons without concurrent substance abuse, 91 (20.0%) were HCV seropositive. Of 58 neurologic disorders identified in the cohort, HIV/HCV co-infected individuals exhibited a higher prevalence of multiple neurologic disorders compared to HIV-infected individuals (60.4% vs. 46.6%, p<0.05) and a higher frequency of seizures (28.6% vs. 17.8%, p<0.05). Unlike HIV mono-infected persons, the risk of seizures was independent of immune status in HIV/HCV co-infected individuals (p<0.05). Symptomatic HIV-associated neurocognitive disorders (sHAND) were more severe among HIV/HCV co-infected persons (p<0.05). HCV co-infection was associated with an increased mortality rate (24.2% vs. 14.5%, p<0.05) with a mortality hazard ratio of 2.38 after adjusting for demographic and clinical variables. Our results indicate that the presence of HCV co-infection among HIV-infected individuals increased neurologic disease burden and risk of death, underscoring HCV's capacity to affect the nervous system and survival of HIV-infected persons.