Inadequate reporting of harms associated with probiotics

Reuters Health Information: Inadequate reporting of harms associated with probiotics

Inadequate reporting of harms associated with probiotics

Last Updated: 2018-07-16

By Will Boggs MD

NEW YORK (Reuters Health) - Reporting of harms associated with prebiotics, probiotics, and synbiotics in randomized controlled trials is lacking or inadequate, according to a systematic review.

Numerous clinical trials have investigated the clinical impact of probiotics, prebiotics, and synbiotics aimed at modifying microbiota in a wide variety of diseases. Little is known about their potential harmful effects, and the Agency for Healthcare Research and Quality concluded in 2011 that there was insufficient evidence to answer questions on the safety of probiotics with confidence.

Dr. Aida Bafeta from INSERM U1153 and Universite Paris Descartes-Sorbonne Paris Cite, Paris, France and colleagues undertook a systematic review of 384 randomized controlled trials assessing probiotics, prebiotics, and synbiotics in order to examine how harms have been reported.

Of these trials, 28% did not give any information related to harms, and 81% did not mention adverse events in the abstract, according to the July 17th Annals of Internal Medicine report.

Almost all trials (97%) failed to describe methods of collecting harms-related information, and 90% did not provide definitions of adverse events or serious adverse events.

Only 18% of studies clearly identified the population included in the safety analysis, 30% reported the number of participant withdrawals due to adverse effects, and only seven of the 53 studies involving hospitalized or critical care patients reported the number of serious adverse events per group.

Reporting of harms-related results was commonly inadequate: 37% of trials used only generic statements; 16% used inadequate metrics; 8% gave only the global total number of adverse events; and 5% provided only global statistical comparisons.

Overall, only nine trials (2%) adequately reported methods of harm assessment, and only nine trials adequately reported all guideline-recommended parameters.

These findings raise "doubts about the confidence we can have in conclusions about the safety of these interventions," the researchers note.

"Considering all these elements, a broad general conclusion that probiotics, prebiotics, and synbiotics are safe cannot be made without discussing safety and toxicology data," they add. "An evaluation of the benefit-risk balance should always be included in randomized controlled trial reports. An international and collective effort is urgently needed."

Dr. Ger Rijkers from University College Roosevelt, Middleburg, The Netherlands recently reviewed regulatory issues on health effects and health claims for probiotics. He told Reuters Health by email, "The data reported are not surprising because they have been the subject of several other recent reviews. What is surprising is that apparently there still is non-consensus (among medical journals) about the level of detail and the format of reporting adverse effects."

"The methodology of clinical and laboratory investigations used to detect any AEs could and should be included in clinical studies submitted to databases like ClinicalTrials.Gov," he said. "Medical journals should be more strict in what they demand in terms of (adverse event) reporting."

Dr. Bafeta did not respond to a request for comments.


Ann Intern Med 2018.

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