Evaluation of publication bias in the assessment of probiotic treatment for gastrointestinal disease in dogs and cats.

Background: Systematic reviews and meta-analyses underpin the evidence-to-decision framework used for guideline development. Publication bias is important to understand when assessing the strength of evidence. Objective: To evaluate the peer-reviewed-journal publication rate of abstracts from 2 veterinary internal medicine conferences regarding probiotic treatment for gastrointestinal disease in dogs and cats. Animals and procedure: Abstracts from the American College of Veterinary Internal Medicine Forum (2000 to 2023) and European College of Veterinary Internal Medicine Congress (2002 to 2023) that reported clinical gastrointestinal disease outcomes of probiotic treatment for dogs, cats, or both were included. PubMed and Web of Science databases were searched to identify corresponding peer-reviewed publications. Results: Twelve abstracts were identified; 6 (50%) were subsequently published as peer-reviewed publications. Five of 6 (83%) that were published reported positive clinical outcomes, whereas 4/6 (67%) that were not published reported no beneficial clinical outcomes. Overall, 5/7 (71%) abstracts that reported a clinical effect were published, compared to 1/5 (20%) that did not. Conclusion: Publication bias complicates assessment of the literature and guideline development. Clinical relevance: The potential impact of publication bias should be considered when evaluating the literature and developing guidelines.