In patients on methotrexate, noninvasive tests might help avoid liver biopsy

By David Douglas

NEW YORK (Reuters Health) - Noninvasive testing may be useful for spotting potential hepatotoxicity and confirming the need for liver biopsy in psoriasis patients on methotrexate sodium, according to Irish researchers who say more studies are needed.

Combining the use of transient elastography (TE) and FibroTest (FibroSURE in the U.S.) with serial procollagen III peptide level measurements reduced the need for liver biopsy in their study, Dr. Maeve Lynch told Reuters Health by email.

In a June 25th online paper in JAMA Dermatology, Dr. Lynch of St Vincent's University Hospital, Dublin and colleagues note that long-term methotrexate monotherapy is often used to manage severe psoriasis. Liver fibrosis can be a side effect.

To assess the potential for noninvasive testing to help avoid biopsies, the team studied 77 patients. Those with abnormal results on TE and FibroTest were considered for liver biopsy. Serial procollagen III peptide (PIIINP) results were also recorded.

Fifty (65%) patients had a valid TE assessment, and nine (18%) had an abnormal result. Seventy-one patients got a FibroTest, and 11 of 70 analyzed (16%) had an abnormal result.

There was no correlation between PIIINP levels and TE or Fibrotest results. In fact, liver biopsy was considered for 10 patients based on persistently abnormal PIIINP results before TE or FibroTest was performed.

Five of these patients went on to have liver biopsies and liver fibrosis was observed in two. Based on subsequently normal TE or FibroTest results within the reference range, say the investigators, three of the liver biopsies could have been avoided.

Two of the 5 patients who had biopsies continued receiving methotrexate, and three, including the two with fibrosis, received alternative systemic or biologic therapies.

The researchers concede that the study had a number of limitations. Only a small group was analyzed and there was missing data. Not all patients were evaluated with PIIINP levels or FibroTest. There was also an interval between the TE and FibroTest assessments.

They call for larger prospective studies but conclude that "the need for liver biopsy could be reduced if abnormalities in at least two tests (serial PIIINP, TE, or FibroTest) are required before biopsy is considered."

Dr. Bruce E. Strober, author of an accompanying editorial, has some caveats. He points out that although attractive in its simplicity, FibroTest has low sensitivity and it can only be perform by validated laboratories.

Dr. Strober, of the University of Connecticut Health Center, Farmington adds that "obesity, a common feature of patients with psoriasis, often renders TE either unreliable or impossible. Furthermore, widespread availability of TE is limited." As a sole test, PIIINP is inadequate for many patients because it lacks sensitivity and has limited worldwide availability.

"Concordant with most other medical specialties," continues Dr. Strober, "dermatology should abandon the liver biopsy.

"Currently available noninvasive measures," he concludes, "need to be used in combination and studied as such in large, prospective, well-controlled studies."

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

JAMA Dermatol 2014.