Just under 9% of HIV-positive individuals in the UK are
co-infected with hepatitis C virus, investigators report in the Journal of Viral Hepatitis.
“In comparison with other large cohort studies, the overall
HCV [hepatitis C virus] prevalence of 8.9% in the UK…is low,” comment the
investigators. They believe that this is because of the low prevalence of HIV
among injecting drug users in the UK.
However, approximately 20% of HIV-positive patients in the
UK have never been tested for hepatitis C, despite guidance that all patients
should be screened annually.
Encouragingly, there was no evidence that co-infection
resulted in a poorer response to antiretroviral therapy.
Liver disease caused by hepatitis C is now a major cause of
illness and death in HIV-positive patients. However, detailed information on
the prevalence of hepatitis C among HIV-positive individuals in the UK is
lacking. There is also little information on hepatitis C testing and the impact
of co-infection on responses to HIV therapy
Therefore investigators from the UK Collaborative HIV Cohort
(UK CHIC) undertook an observational study involving 31,765 patients provided
with care at ten specialist HIV clinics between 1996 and 2007. Prevalence of
co-infection (determined by a positive hepatitis C antibody result), trends in
testing, and responses to HIV therapy were monitored.
Overall, 64% of patients had been tested for hepatitis C at
least once. The proportion of patients screened for the virus increased from 9%
in 1996 to 80% in 2007.
“There has been a clear instruction that all HIV-positive
patients should be screened since at least 2004,” write the investigators. Nevertheless,
“20% of patients under follow-up in 2007 had not apparently ever been tested.
The latest BHIVA [British HIV Association] guidelines recommend screening all
HIV-positive patients at diagnosis, with annual repeat testing in those who are
Testing rates differed according to HIV risk group, and was
highest for gay men (74%), followed by heterosexual men and women (63%).
Although injecting drug use is a well-established risk factor for hepatitis C,
only 50% of individuals with a history of injecting drug use had been tested
for the virus.
However, the investigators think that the true prevalence of
testing in this group is likely to be higher. They comment: “these patients may
be more likely to have been tested previously.” The researchers also suggest
that the higher rates of mortality and loss to follow-up among injecting drug
users could also mean this group were less likely to be screened for hepatitis
Overall prevalence of hepatitis C was 9%, and prevalence was
8% among those who were receiving care in 2007.
By contrast, prevalence in the general UK population is
estimated to be 0.44%. The investigators suggest that the significantly higher
prevalence of the infection among patients in the UK CHIC reflects “the shared
transmission routes of HCV and HIV.”
Prevalence of hepatitis C differed between HIV risk groups.
It was highest in injecting drugs users (84%), followed by gay men (7%), and
heterosexual men and women.
However, the investigators suggest that some hepatitis C
infections in gay men may actually be due to injecting drug use, who suggest
that this behaviour may be “underreported by some MSM [men who have sex with
men], sufficient to place them at risk of HCV infection…underreporting of IDU
as a risk for HCV transmission in MSM may also affect other cohorts.”
Most co-infected patients were men (80%), white (82%), and
their median age was 37. The strongest independent risk factor for co-infection
with hepatitis C was HIV transmission group. Injecting drug users were
significantly more likely to be co-infected than all other risk groups (p <
The impact of co-infection on responses to antiretroviral
therapy was analysed in the 9669 patients who started HIV treatment after 2000.
A total of 4% of these patients were co-infected.
Overall, 91% of patients achieved an undetectable viral
load. Co-infected patients were just as likely as individuals who were only
infected with HIV to achieve this outcome.
There was no association between co-infection and subsequent
rebound in viral load. In addition, CD4 cell count increases were comparable
between co-infected and HIV-mono-infected patients.
“We found no association between HCV co-infection and either
the initial virological response, the rate of viral rebound or the CD4 count
response,” emphasise the investigators. They note that results from the Swiss
HIV cohort study showed that co-infection did not have an impact on virological
responses to therapy.
“The overall cumulative prevalence of HCV of 8.9% in UK CHIC
is lower than other cohorts among whom the proportion of IDU is higher,”
conclude the researchers. However, they emphasise that this rate of
co-infection still “represents a substantial burden of disease.”