Co-infection with HIV and hepatitis C is associated with an increased risk of cognitive impairment, according to research published in the online edition of the Journal of Acquired Immune Deficiency Syndromes.
Investigators from the United States Department of Veterans Affairs compared cognitive function between co-infected men, hepatitis C mono-infected men, HIV mono-infected men and a control group. Co-infection was associated with mild cognitive impairment and significantly poorer scores in a number of tests designed to assess cognitive function. The results are especially interesting as all the men who had HIV and hepatitis C co-infection had well-controlled HIV infection.
“We were able to detect a mild, yet significant impairment in the cognition among the coinfected group,” write the investigators. “Coinfected subjects performed poorly on the attention, executive function, fine motor function and visual and verbal learning memory tests, with significantly lower…scores than either controls or monoinfected subjects.”
Infection with HIV has been associated with cognitive impairment. This is also the case with hepatitis C infection. However, it is currently unclear if co-infected people with well-controlled HIV infection and minimal liver damage caused by hepatitis C are at increased risk of impairment.
Investigators from the Veterans Affairs Medical Center, San Francisco, therefore designed a study involving four groups of male patients aged between 45 and 65 years:
- Co-infected with HIV and hepatitis C (n = 19).
- Hepatitis C mono-infected (n= 17).
- HIV mono-infected (n = 14).
- Healthy controls (n = 28).
All the HIV-positive study participants were taking antiretroviral therapy and had an undetectable viral load. None of the participants had liver cirrhosis or clinical depression. Individuals with drug abuse or alcohol problems were excluded from participation in the study.
“This study represents many American HIV-infected individuals today, who are compliant with their ART [antiretroviral therapy] and live their lives with undetectable viral loads,” comment the investigators.
The participants were evaluated for symptoms of depression. Cognitive function was evaluated in seven domains and an overall global deficit score was also calculated.
People with co-infection had more symptoms of depression than those with hepatitis C mono-infection (p = 0.049) and the control group (p < 0.011).
Moreover, the people with co-infection had worse global deficit scores than individuals with hepatitis C mono-infected (p = 0.015), patients with HIV mono-infection (p = 0.008) and the control group (p < 0.001).
The mean global deficit score for the group with co-infection was 0.77 putting “co-infected patients in the mild cognitive impairment range.”
On the basis of the global deficit score, some 65% of people with co-infection were classified as impaired, compared to 42% of the hepatitis C mono-infected participants, 29% of people with HIV mono-infection and 18% of the control group. The difference between people with co-infection and the control group was significant (p = 0.004).
The people with co-infection also performed more poorly on individual tests.
Compared to the healthy control group, co-infection was associated with worse scores in attention working memory (p = 0.007), executive function (p = 0.011), verbal learning and memory (p < 0.011) and visual learning and memory (p < 0.001).
The investigators suggest that it is the “synergistic effect of HIV and HCV in coinfection that is responsible for neuropsychological deficits in the coinfected population.”
In the hepatitis C mono-infected participants (but not those with co-infection), a higher hepatitis C viral load was negatively associated with attention, executive function and speed of information processing. “These findings imply that HCV viral load may play an important but subtle negative role in cognition, a role which could be better elucidated by experiments specifically designed to assess its impact,” suggest the researchers.
They conclude, “this targeted study indicates that coinfection in males is sufficient to push this group over the threshold into mild impairment and high viral load in HCV monoinfection may impact cognition.”
Sun B et al. Differential cognitive impairment in HCV coinfected men with controlled HIV compared to HCV monoinfection. J Acquir Immune Defic Syndr, online edition. DOI: 10.1097/QAI.0b013e31827b61f1, 2012.