Canadian Physicians Reveal Their Choices for Assessing Liver Fibrosis
According to researchers, the main causes of persistent liver disease include:
- chronic hepatitis B virus (HBV) infection
- chronic hepatitis C virus (HCV) infection
- alcoholic liver disease (ALD)
- non-alcoholic fatty liver disease (NAFLD)
- autoimmune liver disease
Regardless of the instigator of chronic liver disease, liver damage usually proceeds along a common route, causing chronic inflammation, the death of formerly healthy liver tissue and its replacement by scar tissue. This process is called fibrosis. If the underlying cause of chronic liver disease is left untreated, the scarring eventually spreads throughout the liver and this vital organ becomes increasingly dysfunctional. This can lead to serious health complications, including in some cases, liver cancer.
Assessing fibrosis is important so that doctors and their patients can keep abreast of changes to this organ and determine if interventions to improve the health of the liver are having an effect. In the case of ALD and NAFLD, such interventions are behavioural, including cutting back on alcohol and incorporating exercise into daily routines. In the cases of viral infections -- HBV and HCV -- interventions include treatment with antiviral medicines.
Historically, the most highly regarded way of assessing liver fibrosis has been a liver biopsy -- a procedure that involves removing a tiny piece of the liver for laboratory analysis. This procedure can be done relatively quickly. However, liver biopsies can have drawbacks:
- They are invasive.
- They can be painful and costly, particularly if complications occur.
- As the biopsy involves removing only a tiny piece of the liver, damage in other parts of this organ can potentially be missed.
There are several non-invasive means of assessing the degree of fibrosis in the liver, which are largely dependent on blood tests. These include:
- Fibrotest -- this involves measuring levels of several proteins in the blood -- the liver enzyme GGT, the amount of the waste product bilirubin, alpha-2-macroglobulin, apolipoprotein A1 and haptoglobin. In addition to these levels, a person's age and gender are taken into account.
- APRI -- this method involves dividing a person's level of the liver enzyme AST by the number of platelets (used for clotting) in their blood.
Tests that evaluate the physical state of the liver, or stiffness of the liver, can also assess injury. These include:
- Fibroscan -- a specialized form of ultrasound (also called transient elastography)
- Magnetic resonance elastography -- similar to an MRI (magnetic resonance imaging) scan of the liver.
No liver assessment technique or technology is perfect; each one has advantages and disadvantages. However, care and treatment guidelines across high-income regions in North America and Western Europe increasingly call for the use of non-invasive means for assessing liver health. As a result, researchers at McGill University and the University of Calgary were interested in determining how non-invasive technologies were being used to assess damage to the liver. The researchers developed an internet-based survey, which was disseminated with the help of scientific societies such as the Canadian Association of Gastroenterologists (CAG) and the CIHR Canadian HIV Trials Network (CTN). The survey asked doctors who cared for patients with chronic liver disease detailed questions about what they used to assess liver injury in patients.
The researchers found that the use of liver biopsy was still relatively common -- nearly 46% of participants reported using it. However, researchers stated that "non-invasive methods, particularly Fibroscan, have significantly reduced the need for liver biopsy in Canada." Further findings from the survey appear later in this CATIE News bulletin.
Results -- Focus on Who Responded
A total of 237 doctors were invited to participate in the survey. Of those, 104 doctors (44%) chose to do so. The responding doctors had the following organizational affiliations:
- CAG members -- 80%
- CTN members -- 20%
Respondents consisted of 80% men and 20% women.
Other features of the responding doctors were as follows:
- Gastroenterology -- 64%
- Hepatology (liver specialty) -- 16%
- Infectious diseases -- 10%
- Other specialties (family medicine, internal medicine) -- 10%
- University-based hospital -- 51%
- Community hospital or clinic -- 28%
- Private practice -- 21%
Distribution of respondents by province:
- Ontario -- 40%
- Quebec -- 37%
- British Columbia -- 10%
- Alberta -- 7%
- Rest of Canada -- 7%
Types of chronic liver disease treated by the surveyed doctors:
- NAFLD -- 84%
- Autoimmune liver disease -- 81%
- ALD -- 80%
- HCV infection -- 79%
- HBV infection -- 67%
- HIV and HCV and/or HBV co-infection -- 32%
The proportion of physicians who routinely assessed the liver fibrosis of patients by condition was as follows:
- HCV -- 77%
- Autoimmune liver disease -- 60%
- HBV -- 53%
- NAFLD -- 44%
- ALD -- 40%
- HIV co-infection -- 32%
Choice of Tools
The tool most commonly used to assess liver fibrosis was liver biopsy, used by 46% of physicians. This was followed by Fibroscan, used by 39% and Fibrotest, used by 8% of doctors.
The researchers found that overall, the use of non-invasive methods of assessing liver injury reduced the need for liver biopsy by 43%.
Older physicians, hepatologists and infectious disease specialists were more likely to use non-invasive methods than younger doctors. Also, physicians who worked out of a university-based hospital or private practice were more likely to use non-invasive methods.
The survey asked doctors whether non-invasive methods provided an "accurate assessment" of liver fibrosis. Most doctors (83%) agreed that they did while 9% disagreed and 9% neither agreed nor disagreed. Overall, doctors rated Fibroscan as the "best non-invasive method for [assessing the degree of liver fibrosis]."
Nearly 60% of survey respondents did not have a Fibroscan in their clinics. Furthermore, 61% of these doctors disclosed that they did not have "convenient access" to a Fibroscan elsewhere. All doctors who disclosed that they did not have a Fibroscan or convenient access to one stated that should their clinic acquire a Fibroscan or should they otherwise acquire convenient access to one, they would increase their use of it for non-invasive assessment of the liver.
Some doctors surveyed also underscored the need for the development of guidelines to help them use and interpret Fibroscan results.
A U.S. study has found that the cost of a liver biopsy is about $US 1,000 and rises to nearly $US 3,000 when complications occur.
In Canada, according to the researchers, "the [average] cost of a complicated liver biopsy requiring hospitalization [approaches $US 4,000]."
The cost of Fibroscan was a major concern for nearly 15% of doctors surveyed. Fibroscan was developed in France and approved in 2007 for use in that country, where the cost of Fibroscan machines and tests are paid for by the state. Fibroscans have subsequently become widely used throughout Western Europe. Not surprisingly, since that time, the use of liver biopsy as the initial means of assessing liver fibrosis has declined dramatically according to a survey of physicians in France. Fibroscan is approved for use in Canada, but so far, only in Quebec does the healthcare system subsidize its use.
The Canadian survey is useful because it shows that non-invasive means of assessing liver fibrosis are increasingly used and would be used by more doctors should access to Fibroscan become available in their province.
- Sebastiani G, Ghali P, Wong P, et al. Physicians' practices for diagnosing liver fibrosis in chronic liver diseases: A nationwide, Canadian survey. Canadian Journal of Gastroenterology. 2014 Jan;28(1):23-30.
- Castera L, Denis J, Babany G, et al. Evolving practices of non-invasive markers of liver fibrosis in patients with chronic hepatitis C in France: time for new guidelines? Journal of Hepatology. 2007 Mar;46(3):528-9.