<i>Fibroscan</i> finds one in six people with hepatitis C in primary care have advanced liver disease

28 Aug 2018 Keith Alcorn
Originally published on www.infohep.org

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.

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.