by Chael Needle

A new study published in the journal Neurology reports that hepatitis C (HCV) infection has a profoundly deleterious effect on the brain—important news for the approximately one in every three HIV-positive individuals who are also HCV-positive. “Since the advent of HAART, the incidence of AIDS-related dementia has decreased. However, it is too early to say how coinfection of HIV and HCV will affect the burden of cognitive and neurologic problems,” says Dr. Elizabeth Ryan, Ph.D., who works as a neuropsychologist at the Mount Sinai Medical Center in New York City and is the lead author of the study. 

Though this study found that people with HIV/HCV coinfection showed greater cognitive dysfunction, Dr. Ryan says that her research team and others would need to replicate the study to confirm these early results. A range of behavioral and neurological problems has been associated with both HIV and HCV—fatigue, depression, and slowed thought processing, and, in the case of HIV infection, HIV-1 dementia complex.

Says Dr. Ryan about the impetus for the study: “People with HIV/HCV coinfection have accelerated progression of HCV-related liver disease and increased mortality rate compared to HCV or HIV monoinfected patients. Thus, HCV is now a leading cause of morbidity and mortality in HIV patients. Because both HCV and HIV affect cognitive functioning, and because coinfection is so prevalent in the patients we see, we wanted to know if there was a detectable cognitive effect of HCV.”

The researchers studied 116 HIV-positive people (sixty-seven of whom were HCV-positive) enrolled in the Manhattan HIV Brain Bank. Participants underwent a series of neuropsychological tests, interviews, and examinations. The average age of the participants was 43.7 years; all had advanced HIV disease.

Results showed that more than half of the individuals in both groups tested well below normal in several neuropsychological domains. However, there was an overall trend for co-infected patients to perform more poorly. A slightly greater percentage of HCV-positive patients scored 1.5 or more standard deviations below published norms for psychomotor speed, working memory, verbal fluency, as well as learning and memory retrieval.

Researchers also looked at executive functioning, a cognitive domain which includes problem solving and hypothesis testing, and found a significant difference between those with HIV and those with HIV/HCV. Forty-three percent of participants coinfected with HIV/HCV scored 1.5 or more standard deviations below the norm compared to twenty-nine percent of those who were not HCV-positive. Forty-six percent of coinfected participants met the criteria of HIV-1-associated dementia, while only ten percent of HCV-negative participants did. Neither liver disease nor substance abuse, however, seemed to contribute to these differences.

“Treatment of chronic HCV may improve the life expectancy of people living with HIV. The AIDS Pegasys Ribavirin International Coinfection Trial (APRICOT) demonstrated that pegylated interferon alfa-2a plus ribavirin was an effective treatment: Forty-nine percent of HIV/HCV coinfected patients showed a sustained virologic response,” says Dr. Ryan. “Whether pegylated interferon alfa-2a plus ribavirin also ameliorates cognitive problems is unknown at present, and will be a topic of future study.” 

Another future study will be designed to evaluate the neuropsychiatric profiles of coinfected patients based on HCV viremia, a factor unknown in the first study. “Knowing the HCV viral load will assist us in learning whether cognitive problems are a function of the amount of virus or just related to its presence regardless of the load. I will soon be opening a study to assess the relationship between HCV viral load and cognitive problems,” says Dr. Ryan.

For more information about enrollment in Dr. Ryan’s study, please call (646) 345-5450.

Chael Needle wrote about anemia and AIDS in the September issue.

October 2004