Scan may help many with NAFLD avoid biopsy

Last Updated: 2016-03-30

By Anne Harding

NEW YORK (Reuters Health) - A non-invasive test could help rule out advanced fibrosis in many patients with nonalcoholic fatty liver disease (NAFLD), according to new findings.

Fibrosis stage is the key predictor of outcomes in patients with NAFLD, and guidelines recommend liver biopsy for patients with elevated NAFLD fibrosis scores (NFS), Dr. Elliot B. Tapper, of Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, and colleagues explain in their report online March 15 in the American Journal of Gastroenterology.

Alternatives to biopsy are needed, they add, given that many patients will refuse them, they are expensive and can be risky, and are often subject to sampling error.

Vibration controlled transient elastography (VCTE), a Food and Drug Administration-approved tool, could be used along with NFS to estimate liver fibrosis, and possibly avoid biopsy in some patients, the researchers say. While studies from France and Canada have shown that the test performs well in populations with a body mass index (BMI) above 30 kg/m3, they add, concerns have been raised that VCTE may not perform as well in U.S. populations with higher BMIs.

To investigate, Dr. Tapper and his team looked at 164 U.S. patients with biopsy-proven NAFLD who underwent VCTE at baseline and again six months later. They defined reliable liver stiffness measurements (LSMs) as 10 valid measurements with an interquartile range of 30% or less of the median.

Just under three-quarters of the patients had reliable LSMs. Median LSMs were 6.6 kilopascals in patients with advanced fibrosis, versus 14.4 kPA for patients without advanced fibrosis. The optimal cutoff for advanced fibrosis of 9.9 kPA had 95% sensitivity and 77% specificity. None of the patients with LSM below 7.9 kPA had advanced fibrosis.

Using VCTE for risk stratification would have avoided the need for biopsy in at least the 45.1% of patients who were classified correctly as having a low risk for advanced fibrosis, the researchers report.

Area under the receiver operating curve was 0.93 for detecting advanced fibrosis in patients with reliable VCTE, versus 0.77 for the NFS (p=0.01). The researchers also found that LSM improved in patients who had lost at least 5% of their body weight at six-month follow-up.

VCTE "is a very good tool for telling a significant proportion of the population that they do not have advanced fibrosis," Dr. Tapper told Reuters Health in a telephone interview.

People whose scans did not yield a reliable LSM tended to have a BMI of 39 or higher, the researcher noted, suggesting that patients with a BMI of 38 or less are the best candidates for the test.

The authors reported no funding or disclosures.

SOURCE: http://bit.ly/1RqWw5d

Am J Gastroenterol 2016.