Reuters Health Information (2013-06-04): Blood tests diagnose fibrosis, cirrhosis in chronic hepatitis C
Drug & Device Development
Blood tests diagnose fibrosis, cirrhosis in chronic hepatitis C
Last Updated: 2013-06-04 11:33:26 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Several blood tests, alone and in combination, can diagnose hepatitis C virus (HCV)-related fibrosis or cirrhosis, a systematic review indicates.
The blood tests might not be as good for ruling out the conditions, however.
"We found that a number of indices performed similarly well for identifying HCV patients with clinically significant fibrosis or cirrhosis," Dr. Roger Chou told Reuters Health in an email. "Relatively simple tests based on a few commonly obtained (and relatively inexpensive) lab tests were about as accurate as indices based on more tests, tests not commonly obtained, and proprietary panels."
The aspartate aminotransferase-platelet ratio index, or APRI, one of the most studied of the indices, is based on two common lab tests (AST and platelet count), and would be a reasonable option, said Dr. Chou, from Oregon Health & Science University in Portland.
As part of a review commissioned by the Agency for Healthcare Research and Quality on HCV screening, Dr. Chou and Ngoc Wasson reviewed the evidence on the accuracy of blood tests to diagnose fibrosis in patients with chronic HCV infection.
Their June 4 Annals of Internal Medicine report included 172 studies and four subsequent reports from three of these studies. Fifteen studies were rated as good quality, five as poor quality, and the remainder as fair quality.
For fibrosis, the following yielded median specificities greater than 0.9, positive likelihood ratios from 5.1 to 10, and negative likelihood ratios from 0.48 to 0.81: a platelet count <163,000, an age-platelet index score of 6.0 or greater, an APRI score >1.5, a FibroTest score >0.70, and a Forns index score >6.9.
For cirrhosis, an APRI score >2.0 was associated with a specificity of 0.94, whereas platelet counts <155,000, age-related platelet index scores of 6.0 or greater, and Hepascores <0.801 were associated with median specificities ranging from 0.86 to 0.88. Positive likelihood ratios for these tests ranged from 5.1 to 8.0, and negative likelihood ratios ranged from 0.25 to 0.55.
Only the FibroIndex and FibroTest were associated with negative likelihood ratios for fibrosis in the moderately useful range (0.10 to 0.20), the researchers note, "suggesting that blood tests may be somewhat more useful for ruling in than ruling out fibrosis."
In direct comparisons of various tests for fibrosis and cirrhosis, the differences were small or nonexistent, but in various studies, diagnostic accuracy was somewhat higher for combinations of indices.
"Factors that may affect use or selection of blood tests include availability and cost, given the variability in component blood tests, the number of tests required, and proprietary status," the authors wrote. "Studies that evaluate the virologic and clinical outcomes of antiviral treatment in HCV-infected patients who have not had liver biopsy are needed to further define optimum work-up strategies."
"If clinicians implement the CDC recommendations to perform HCV screening in all persons in the 'baby boomer' birth cohort, we will identify many more patients with HCV who will have to make decisions regarding antiviral therapy," Dr. Chou said. "In addition, more effective, all-oral, interferon-sparing antiviral regimens are expected to become available in the near future, so patients who have been deferring therapy due to concerns about interferon-related side effects may soon be making decisions about treatment. Information about fibrosis stage is important for knowing who is at risk for disease progression or complications related to HCV."
Dr. Chou added, "We didn't look at imaging tests which are also being used; some studies have looked at using combinations of indices which may increase the accuracy; we also need studies to evaluate how patients who receive antiviral treatment without undergoing biopsy fare compared to those who undergo antiviral treatment and had a biopsy done to help guide treatment decisions."
Dr. Jean-Pierre Zarski from Grenoble University Hospital in France, who has published research on blood tests for fibrosis, told Reuters Health by email, "These tests can be used in patients with viral hepatitis and maybe NASH (nonalcoholic steatohepatitis) for the assessment of liver fibrosis when the patient has no comorbidities and no other associated liver disease."
"We currently use FibroTest and Fibroscan and sometimes Fibrometer for assessing liver fibrosis," Dr. Zarski said. "For following patients under treatment, it's more complicated to clearly identify patients with fibrosis improvement."
Ann Intern Med 2013.