Study Shows Hepatitis C Doesn't Cause Mental Impairment in HIV Coinfected Patients

Hepatitis C does not contribute to mental impairment in patients who are coinfected with HIV when there is an absence of substantial liver damage, according to a study published online in the journal Neurology.

In a news release that accompanied publication of the study results, lead author David Clifford, MD, of the Washington University School of Medicine in St. Louis, said, “Hepatitis C infection has serious long-term side effects, such as damage to the liver, but our research indicates that it does not affect the brain.”

People with HIV are living longer and as they age many show signs of impaired mental function that includes memory loss, mood swings and impaired thinking, noted the Washington University statement about the study. Scientists are studying potential causes including long term infections with other pathogens that may affect the brain.

Determining the cause of mental impairment among patients with both HIV and hepatitis C can be difficult if the patients also abuse drugs that can harm the brain. About 1 in 3 patients with HIV also have hepatitis C and today injection drug use and the sharing of tainted needles is the most common transmission of the hepatitis C virus, according to the statement.

Researchers looked at mental performance of chronically HIV-infected patients who were enrolled in the multicenter CHARTER study of long term neurological effects of HIV infection.They conducted neurocognitive testing of 1,582 participants who had previously been tested for the hepatitis C virus antibody.

Participants took a 2.5-hour written test and were examined physically by medical professionals. The exams assessed ability to express oneself, make decisions and learn and retain new information using multiple types of memory, physical movement ability and muscle control.

Among the participants, 408 were seropositive for the hepatitis C virus and 1,174 were seronegative. Study results indicated that global deficit scores and the proportion of individuals who were impaired were the same in the seropositive and seronegative groups.

“In all, we looked at seven domains of mental function,” Clifford said in the statement. “We studied their overall performance and looked at each domain individually and found no evidence that the group with hepatitis C performed worse.”

Researchers concluded that hepatitis C coinfection of patients with HIV does not contribute to neurocognitive impairment, “at least in the absence of substantial”hepatitis C-associated liver damage, which was not evident in the studied cohort.

“If a hepatitis C infection gets to the point where it damages liver function, the resulting inflammation might well contribute to mental impairment,” Clifford said. “Beyond that, though, it doesn’t seem to be an active collaborator in the harm HIV does to the brain.”

With hepatitis C ruled out, Clifford and colleagues plan to now focus on the immune responses triggered by HIV in the brain and the bowel when infection first sets in. They theorize that the brain could be adversely affected by early inflammation responses leading to chronic inflammation that can damage the brain.