Meta-analysis suggests synbiotic benefit in atopic dermatitis

Last Updated: 2016-01-27

By Anne Harding

NEW YORK (Reuters Health) - A new meta-analysis supports the use of synbiotics to treat atopic dermatitis (AD), researchers say.

"Using synbiotics, the combination of prebiotics and probiotics, is definitely helpful to treat atopic dermatitis," Dr. Maria Garcia-Romero of the National Institute of Pediatrics in Mexico City, one of the new study's authors, told Reuters Health. "Particularly when you are using combinations that have two or more bacterial strains, and if the children are older or equal to one year of age."

AD prevalence among infants and children is estimated to be 15% to 20%, Dr. Garcia-Romero and her colleagues write in their report, online January 25 in JAMA Pediatrics. There is some evidence linking AD to altered gastrointestinal microbiota, they add, and some studies suggest that probiotics are helpful for AD. Giving probiotics along with prebiotics - the "food" that helps good bacteria grow - could produce a stronger effect, they suggest.

To investigate, the researchers analyzed 257 abstracts and identified six treatment studies including 369 patients and two prevention studies including 1,320 children. A pooled analysis of the treatment studies found eight weeks of treatment reduced Severity Scoring of Atopic Dermatitis (SCORAD) index by 6.56 (p=0.008).

There was significant heterogeneity among the studies. The beneficial effect was significant only in the studies in which mixed bacteria were used (-7.32, p=0.03) and in children aged one year or older (-7.37, p=0.048).

The prevention studies found a pooled relative risk ratio of 0.44 for AD in children treated with synbiotics, which was not statistically significant (p=0.26).

Some doctors use synbiotics empirically for treating or preventing AD, Dr. Garcia-Romero said, but it's likely that more use probiotics, which are more widely available. Synbiotics are available on the market in the U.S. and in parts of Europe, she added, but not in Mexico. Most of the products used in the studies analyzed had been specifically prepared in the research setting.

Dr. Garcia-Romero said she and her colleagues would like to conduct a clinical trial of synbiotics for AD in Mexico, where it is less prevalent and tends to be less severe than in the US.

Dr. Mimi Tang of the Royal Children's Hospital in Parkville, Victoria, Australia, co-authored an editorial accompanying the study. She argues that the findings do not support the use of synbiotics for preventing or treating AD.

"The meta-analysis had highly significant heterogeneity and there is some concern regarding publication bias (although the authors of the article do not say this)," Dr. Tang told Reuters Health by email. "The major barriers currently are to know which probiotic and which prebiotic to put together in a synbiotic for treatment."

She also questioned the validity of pooling the results of studies of different types of probiotic and prebiotic combinations.

"Individual probiotics have very species-specific effects so what is shown for one bacteria will not necessarily be so for another bacteria," she said. "A good example of this is that certain probiotics (e.g. L. rhamnosus GG, L rhamnosus HN066) have been shown to prevent eczema, yet L acidophilus increased the risk of sensitization. So some bacteria could worsen the likelihood of a condition rather than preventing it."

She concluded: "There is currently insufficient evidence to recommend use of synbiotics for the prevention or treatment of allergic disease at this time."

Dr. Garcia-Romero and her colleagues do not report any conflicts of interest. Dr. Tang has served on medical advisory boards of Nestle Nutrition Institute and Danone Nutricia, and has received honoraria for presenting at symposia sponsored by Danone Nutricia.

SOURCE: bit.ly/23sKxsU and bit.ly/1nxy8DW

JAMA Pediatr 2016.