Effect of interferon-free therapy on cognition in HCV and HCV/HIV infection: A pilot study

Methods.

We conducted an open observational trial with HCV and HCV/HIV coinfected patients and planned HCV treatment. Patients with liver cirrhosis (defined as fibroscan >12.5 kPa), a history of substance dependence, or cerebral diseases were excluded. HIV-infected patients had to have undetectable plasma HIV levels for at least 6 months. We assessed a comparison group of healthy controls (n = 30) for baseline, but not for follow-up. The neuropsychological test battery included standardized tests and—to minimize practice effects—alternate versions for follow-up testing, covering 7 domains (table). We used age-corrected norms. To test for baseline and longitudinal differences, we used t tests for dependent and independent samples, respectively. Participants completed self-report assessments of cognitive symptoms, instrumental activities of daily living, fatigue, depression, and quality of life. Testing sessions took place at baseline and at the earliest 12 weeks after the end of HCV treatment.

Results.

We have seen 25 HCV-positive outpatients between 2015 and 2016 before treatment. Fifteen were coinfected with HIV. All but one participant were male. Groups did not differ significantly in age or years of education (patients [mean age 43.8 years (SD 11.7); mean education 15.1 years (SD 2.1)]; controls [mean age 39.5 years (SD 9.9); mean education 16.1 years (SD 2.0)]). Mean nadir CD4 of the coinfected group was 328 cells/μL (SD 215); baseline CD4 cell count was 846 cells/μL (SD 242) and remained stable over time. At baseline, the patient group showed significantly poorer performance in the domains of visual and working memory, processing speed, attention, and executive functioning (table). We did not observe a difference between monoinfected and coinfected patients.

To date, 12 participants have completed therapy and undergone follow-up. Treatment regimens were well-tolerated and included the following: ombitasvir/paritaprevir/ritonavir + ribavirin (n = 2), ledipasvir/sofosbuvir (n = 9), or sofosbuvir + ribavirin (n = 1). Mean therapy duration was 10 weeks (8–12 weeks); all patients were HCV-RNA-negative at week 12 after treatment completion.

At follow-up assessment, patients did not show cognitive decline in any domains compared to baseline; neither did any patient report subjective impairment during or after the therapy. On the contrary, 2-tailed t tests indicate a significant (p < 0.05) improvement in the domains visual memory, processing speed, attention, and executive functioning. In addition, we observed a significant (p = 0.022) decline in self-reported fatigue severity. There was no significant change in the level of depression, but an increase in self-reported quality of life.

Discussion.

In this study, we investigate the effect of an interferon-free treatment on cognitive function in HCV-monoinfected and HCV/HIV coinfected patients. Our data show that HCV-infected patients without comorbidities had significantly poorer cognitive performance than controls. Against our expectations, HIV coinfection did not increase the extent of cognitive deficits. These findings partially contradict conclusions made by other studies. A recent study⁶ showed that HCV coinfection did not have an effect on cognitive function in a cohort of HIV-infected patients, which led the authors to question an influence of HCV on cognition per se.

In contrast, our data suggest a significant influence of HCV infection on cognitive function, which seems to outweigh that caused by HIV infection. Our first follow-up data support this assumption, showing an improvement in those cognitive domains that were impaired before HCV eradication. Our study was explicitly designed to detect differences attributable to HCV eradication. In contrast to the cross-sectional approach of most previous studies, we therefore chose a longitudinal approach.

Nevertheless, these first data have to be interpreted carefully due to small sample size. Practice effects might partially contribute to the observed improvements. However, reported effect sizes are relatively small (Cohen d = 0.00–0.24)⁷ compared to the ones seen in our cohort (d = 0.20–1.79). To verify an improvement, more follow-up data need to be considered using a reliable change index approach⁸ to differentiate between practice effects and treatment-related cognitive changes.