Is Interferon Therapy Behind Cognitive Decline in HCV Patients?

In an article published in the journal Neurology, a group of researchers set out to understand how interferon-free therapy affects patients infected with hepatitis C (HCV) or co-infected with HCV and HIV. They found that it could reverse the cognitive declines that appear to accompany HCV infection or co-infection.

According to a study published in April 2016 in World Journal of Hepatology, infection with HCV may causes neurological complications in many patients. They state that neurological complications can manifest through cognitive impairment or sensory or motor peripheral neuropathy.

Now, Felix Kleefeld, of Berlin, Germany, and colleagues examined how eradicating HCV affected the cognition of patients in a study published in Neurology in December 2016. Interferon treatment, according to the researchers, poses the risk of cognitive impairment, yet there have been few, if any, studies addressing interferon-free treatment and cognitive deficits in patients with HCV.

Previous studies have shown that HCV replication is associated with neuro-inflammatory conditions, which the researchers believe could lead to cognitive deficits. Some studies have demonstrated that cognitive impairment for patients with HIV co-infection is even more common than among those with single HCV infection.

This observational trial involved 25 patients with HCV, 15 of whom were co-infected with HIV. Patients had an average of 43.8, and only one patient was female. They were matched with 30 healthy controls.

“At baseline, the patient group showed significantly poorer performance in the domains of visual and working memory, processing speed, attention, and executive functioning,” the researchers wrote. There did not appear to be a difference in the cognitive function between patients solely infected with HCV and those co-infected with HCV and HIV.

Among the findings researchers said are worth further study, they noted that they were surprised to find no difference in the extent of cognitive deficits between HCV-only patients and those with HIV co-infection. The implication of that finding partly contradicts conclusions of some previous studies. They added that “our data suggest a significant influence of HCV infection on cognitive function, which seems to outweigh that caused by HIV infection.” The team contended that the first round of follow-up results supported that assumption.

The small sample size of the present study is another important factor to consider, as are practice effects, which could potentially contribute to the cognitive improvements the researchers observed in the patients.

“To verify an improvement, more follow-up data need to be considered using a reliable change index approach to differentiate between practice effects and treatment-related cognitive changes,” the researchers concluded.

As of the date the study was written, 12 of the patients with HCV had successfully completed their therapy and undergone a follow-up assessment to determine whether or not cognitive decline had progressed during treatment. No signs of continued decline were found, but there was some indication of improvement in visual memory, processing speed, attention, and executive functioning. Additionally, the patients reported significantly less fatigue, and while there was no change in the levels of depression, the researchers say there was “an increase in self-reported quality of life.”