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.
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
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=
- 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
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