MappingHCV.com, supported by AbbVie and
launched at The Liver Meeting, is a new interactive online resource featuring
national US and state-level data on HCV screening, diagnosis and treatment.
AbbVie
researchers analysed two large national laboratory datasets that included more than
17 million HCV antibody tests and 1.5 million HCV RNA tests between 2013 and
2016. In line with Rosenberg's findings, this analysis showed that West
Virginia and Washington, DC, had the highest overall prevalence of active HCV
infection, while West Virginia and Kentucky had the highest prevalence among
adults age 30 to 52 years.
Two other studies based on the same datasets, looking at the US HCV care
cascade, were presented at The Liver Meeting.
Mark Sulkowski of Johns Hopkins Hospital in Baltimore and colleagues
aimed to identify gaps in HCV screening and diagnosis. Traditionally, baby boomers born between
1945 and 1965 have had the highest HCV prevalence in the US, and guidelines
recommend that everyone in this age group should be tested at least once.
People in other age groups are advised to be screened if they are known to be
at risk.
The researchers found that the number of people screened per year
steadily increased from over 4 million in 2013 to over 5 million in 2016, but
the proportion who were HCV antibody positive remained roughly stable (from 5.3%
to 5.6%). Some states that implemented new screening policies saw large jumps, for
example Connecticut (from 17 to 28 people screened per 1000 residents).
However,
while the proportion of HCV antibody positive baby boomers (age 48 to 71)
decreased from 9.1% to 8.1%, the proportion of positive young adults (age 18 to
39) rose from 2.8% to 3.9%. In the younger group, rates increased from 4.1% to 5.6% among men and from 2.2% to
3.0% among women.
The share
of antibody positive people who received confirmatory HCV RNA testing rose
dramatically, from 45.0% in 2013 to 76.5% in 2016. The researchers attributed
this increase in part to wider use of 'reflex' or automatic HCV RNA testing if
a blood sample tests antibody positive; people are often lost to follow-up if
they have to come back for a separate confirmatory HCV RNA test.
"While rates of HCV antibody screening and confirmatory
RNA testing are improving, results from this study confirm a rising HCV
epidemic among young adults," the researchers concluded. "Revisions
to the current recommendations for HCV antibody screening should be considered
to improve detection of active HCV among younger persons for whom risk behaviours
(such as injection drug use) may not be reported due to stigma."
Nancy
Reau's team looked at linkage to care among people who tested HCV antibody
positive.
As noted,
76.5% received
confirmatory HCV RNA testing in 2016 and 63.9% were found to have active HCV
infection. Of these, 17.4% saw a gastroenterologist, hepatologist or other specialist,
while about 40.5% saw a primary care provider (PCP).
The proportion who saw a specialist in 2016 declined from 2013 while the
proportion who saw a PCP rose – perhaps reflecting growing knowledge about DAA
treatment and data showing that primary care
providers can manage hepatitis C treatment with similar success.
Nonetheless, patients remained much more likely to receive treatment if
they saw a specialist. Further, young adults were less likely than baby boomers to receive treatment, regardless of
whether they saw a specialist (22.6% vs 32.0% treated) or a PCP (4.5% vs 8.1%, respectively).
"Undiagnosed and untreated
young adults represent a growing proportion of the chronic HCV patients and
addressing gaps in care among young patients is essential to treating HCV
infection," the researchers concluded. "These
findings suggest that health systems need to not only redouble efforts to
diagnose and treat baby boomers, but also develop additional screening efforts
among younger patients."