Measuring liver stiffness in primary care using Fibroscan is feasible and detects
numerous cases of undiagnosed but advanced liver fibrosis, Australian
researchers report in the journal BMJ
Open this month.
Despite availability of direct-acting antivirals, many people diagnosed
with hepatitis C remain untreated. In many cases, people with hepatitis C may
be engaged in primary health care but may not have sought specialist care, either
because of the cost and distance of travel, or because of a perception that
their condition is not causing major health problems. The underlying progression
of liver disease may not be evident either to the patient or their primary care
physician.
Due to a lack of knowledge of liver disease status,
treatment may be delayed until advanced cirrhosis has developed, reducing the
likelihood that hepatitis C can be cured with a first course of treatment, and
raising the risk of hospitalisation or death due to decompensated cirrhosis and
liver failure.
Glossary
- decompensated cirrhosis
The later stage of
cirrhosis, during which the liver cannot perform some vital functions and
complications occur. See also ‘cirrhosis’ and ‘compensated cirrhosis’.
- FibroScan
A non-invasive test, used instead of a biopsy, to measure the stiffness
or elasticity of the liver using an ultrasound probe.
- hepatocellular carcinoma (HCC)
Liver cancer. A long-term complication of chronic inflammation of the liver or cirrhosis.
Staging liver disease in the community setting is also essential
if direct-acting antiviral treatment is offered in primary care, to distinguish
patients with cirrhosis who may need longer treatment courses. Expanding the
provision of treatment through primary care has been identified as an essential
step in eliminating hepatitis C, especially in countries like Australia where
people may live hundreds of miles from the nearest specialist liver clinic.
Australian researchers wanted to find out whether advanced
fibrosis could be identified accurately in primary care using Fibroscan, a non-invasive imaging tool that
uses sound waves to determine the stiffness of the liver. Fibroscan measurement of liver stiffness has been validated as an
accurate measure of liver damage when used by specialists in a hospital setting
but its performance in a community setting is unknown.
The study also investigated whether liver stiffness
measurements in primary care predicted subsequent liver-related events such as
decompensation or development of hepatocellular carcinoma (HCC).
The study recruited 780 patients from 21 primary care
practices in the state of Victoria, representing 4.5% of the estimated
population with hepatitis C in the practice catchment areas. An additional
control group of 272 hospital patients was also recruited. Primary care
recruitment sites included opioid substitution clinics as well as general
medical practices.
The community cohort had a median age of 43 years and 71%
were male. Only 34% had received a previous liver ultrasound and only 54% had
undergone routine blood tests for liver enzyme levels in the previous two
years.
Fibroscan
measurement was achieved successfully in 99.7% of cases and 59% of community
participants were found to have a liver stiffness measurement of 8kPA or below,
24.6% a measurement of 8-12.5kPA and 16.5% a measurement above 12.5kPA, indicating
advanced liver fibrosis. In comparison, 20.2% of the hospital cohort had a liver
stiffness measurement of 12.5 kPA or above.
Multivariate analysis found that higher alcohol use (odds
ratio 2.13, p < 0.001), older age (OR 1.07, p < 0.001), higher body mass
index (1.13, p = 0.001) and ALT of two times or more above the upper limit of
normal (OR 3.06, p < 0.001) were independent predictors of a liver stiffness
measurement of 12.5 kPA or above. The relationship between higher liver
stiffness measurement and age was especially pronounced; whereas only 8.4% of
those under 40 had a measurement of 12.5 or above, 42% of those in their 60s
had a measurement of 12.5 or above.
Participants were followed for a median of 15 months after
their liver stiffness measurement. During follow-up 421 people began
direct-acting antiviral therapy (169 in specialist care and 252 in primary
care). Liver-related events occurred in 9.3% of those with liver stiffness
measurements of 12.5 kPA or above and a liver stiffness measurement of 12.5 kPA
or above was associated with a 56-fold increase in the rate of liver-related
events compared with lower levels of liver stiffness.
A liver stiffness of 24 kPA or above was the strongest
predictor of a liver-related event – people with this degree of liver stiffness
were over 150 times more likely to suffer some form of liver-related event in
the follow-up period compared with people with levels of liver stiffness below
12.5 kPA (hazard ratio 152, 95% CI 15-1523, p < 0.001), although the
confidence interval on this estimate was very wide.
The investigators say that their findings show the extent of
undiagnosed advanced liver disease in people receiving primary care. The
prevalence did not differ between community and hospital cohorts and
approximately one in six people had advanced liver disease.
The findings also demonstrate that measuring liver stiffness
in community settings is feasible and provides further evidence for targeting
screening. People aged 40 and over, people with high alcohol intake and people
with co-factors for metabolic syndrome might be prioritised for community
screening, the authors suggest.