Comparison of cognitive performance in HIV or HCV mono-infected and HIV-HCV co-infected patients

Our aim was to explore the interplay between human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections in the expression of cognitive disorders. We performed a multi-centre cross-sectional study, enrolling three groups of asymptomatic outpatients matched for age and education: (1) HIV mono-infected; (2) HCV mono-infected; (3) HIV-HCV co-infected. All subjects were subjected to the Zung depression scale and a comprehensive neuropsychological battery. A total of 50 patients for each group were enrolled. Patients in the three groups did not significantly differ in the main common demographic and clinical characteristics, except for a lower proportion of past injecting drug use (IDU) in group 1 (4 %) in comparison to groups 2 (38 %, p < 0.001) and 3 (78 %, p < 0.001), a longer duration of HIV infection in group 3 in comparison to group 1 (p < 0.001) and a longer duration of HCV infection in group 3 in comparison to group 2 (p = 0.028). Overall, 39.3 % of patients showed minor cognitive impairment, with a higher proportion in group 3 (54 %) when compared to groups 1 (28 %, p = 0.015) or 2 (36 %, p = 0.108). Patients in group 3 [odds ratio (OR) 3.35, p = 0.038 when compared to group 1] and those with higher depression scores (OR 1.05, p = 0.017) showed an increased risk of cognitive impairment after adjusting for education and past injection drug use. In particular, group 3 showed worse performance in psychomotor speed tasks when compared to group 1 (p = 0.033). A worse cognitive performance in HIV-HCV co-infected patients was observed, suggesting an additive role of the two viruses in the pathogenesis of cognitive disorders.