Miller, Larry E.Clinical trials of therapies intended to alleviate symptoms of irritable bowel syndrome (IBS) are prevalent. However, the ideal study design remains elusive since there is no obvious pathophysiological target and no universally accepted endpoint to assess symptom improvement in IBS. The purpose of this paper is to identify and discuss the most problematic issues in the design of clinical trials intended to evaluate the effectiveness of treatments for IBS symptoms. Lack of standardized diagnostic criteria, symptom variability, heterogeneous subject characteristics, large placebo effects, lack of statistical power, inappropriate endpoint selection, and poorly selected study design are the most critical issues that may confound study outcomes in IBS clinical trials.Keywords Clinical trial, irritable bowel syndrome, study designAnn Gastroenterol 2014; 27 (4): 338-345text/htmlapplication/pdfapplication/vnd.openxmlformats-officedocument.wordprocessingml.documenthttp://www.annalsgastro.gr/index.php/annalsgastro/article/view/1688engHellenic Society of Gastroenterology1792-74631108-7471Annals of Gastroenterology; Volume 27, No 4 (2014); 338Study design considerations for irritable bowel syndrome clinical trialsinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersion2014-09-30Δημοσίευση σε περιοδικόPublication in journalΓαστροεντερολογίαGastroenterologyisi -Gastroenterology & Hepatology covers resources on the anatomy, physiology, biochemistry, and pathology of the digestive system. This category includes specific resources on the prognosis and treatment of digestive diseases; stomach ulcers; metabolic, genetic, infectious and chemically induced diseases of the liver; colitis; diseases of the pancreas and diseases of the rectum.ΑναφοράReportΕλληνική Γαστροεντερολογική ΕταιρίαGreek Aggregator OpenArchives.gr | National Documentation Centre (EKT)other