Design of treatment trials for functional gastrointestinal disorders

Until recently many clinical trials of functional gastrointestinal disorder s (FGIDs) suffered from important weaknesses in trial design, study executi on, and data analysis. This makes it difficult to determine whether truly e fficacious therapies exist for these disorders. One of the important method ologic problems is the absence of validated outcome measures and lack of co nsensus among stakeholders on how to measure outcome. Currently much of the effort is being put into the development of validated outcome measures for several of the FGIDs. The randomized, controlled trial with parallel group s is the design of choice. In this report, guidelines are given for the bas ic architecture of intervention studies of FGIDs. Further studies on design issues are required to ensure the recommendations will become evidence bas ed in the future.