People living with HIV are infrequently screened for hepatitis C virus (HCV) infection,
according to US research published in the online edition of Clinical Infectious Diseases. The
retrospective study examined screening practices at seven primary care sites
between 2000 and 2011. The frequency of testing increased, but practice varied
considerably between sites, and in some instances individuals with high-risk
behaviours were infrequently tested for HCV.
“Screening for
incidence HCV is variable across sites and improvement in frequency of
screening is also variable, highlighting the a need for US-based guidelines to
inform HIV practice,” write the authors.
An editorial in
the same issue of the journal stresses the importance of prompt HCV diagnosis
in people living with HIV.
Many people living with HIV have a high risk of infection with hepatitis C virus. Injecting drug use is a
recognised risk factor for the acquisition of the HCV and there is also
an epidemic of sexually transmitted HCV among gay men living with HIV in some European
and US cities.
US guidelines
recommend that people living with HIV at “high risk” of HCV should be
considered for annual HCV antibody screening. However, the definition of high
risk is unclear, and current testing practices are unknown. Because of this
uncertainty, a team of investigators designed a retrospective study involving
70,000 people living with HIV who received primary care at seven sites across
the US between 2000 and 2011. They measured rates of HCV screening using
antibody or RNA tests on entry to care, and for people who did not have HCV at
baseline, levels of subsequent testing. The factors associated with testing
were also analysed, and the investigators also examined whether elevations in
liver enzyme levels (ALTs) – a possible indication of recent HCV infection –
triggered further diagnostic tests.
Rates of screening
for people newly enrolled in care were good, with 85% undergoing HCV antibody
or RNA testing within three months of establishing links with a provider. But
analysis of the 9000 people who did not have HCV and who remained in care
for at least one year showed that only 56% received any additional HCV
screening during follow-up.
Rates of follow-up
testing ranged between sites from a low of 35% to a high of 79%.
A number of risk
factors and clinical characteristics were associated with HCV screening during
follow-up. These included reporting unprotected anal intercourse (OR = 1.31;
95% CI, 1.08-1.59); amphetamine use (OR = 1.86; 95% CI, 1.42-2.44); having an
AIDS diagnosis (OR = 1.16; 95% CI, 1.04-1.31); and a history of non-HCV-related
liver disease (OR = 3.41; 95% CI, 2.51-4.63). People who reported injecting drugs were more
likely to be screened than gay men or heterosexual risk groups.
Surveillance
screening increased over time, and between 2008 and 2011 the rate of screening
varied between 0.24 to 0.63 screens per person year. The median number of
screens per person also increased at most sites, as did the proportion of
people undergoing HCV testing at fixed time points.
“Surveillance
screening for incident HCV infection varies substantially between clinical
sites – even among those who report high-risk characteristic such as current
amphetamine use and anal sex with inconsistent condom use,” note the authors.
HCV screening of people with elevations in ALTs was infrequent: only 27% of people with levels
above 100 iu/l and a fifth of those with a measurement above 400 iu/ml
underwent HCV antibody or RNA testing within twelve months. Screening rates
were similar when analysis was restricted to gay and other men who have sex
with men.
“It appears that
providers in the US do not routinely use ALT as a screening test for incident
HCV,” comment the investigators. They conclude national HCV screening
guidelines for people living with HIV are needed, “informing whom to screen, how
frequently to screen them, and what screening tests to use.”