title: Review article: Single subject trials as a research instrument in gastrointestinal pharmacology.
abstract: The single subject trial is a randomized controlled trial carried out in the individual patient, and the result obtained is specific to the individual patient and the drug being investigated. This type of trial offers a supplement to traditional parallel group trials, especially in patients with heterogeneous disorders, often characterized by varying treatment responses and/or high placebo response rates. Pooled results from several individual single subject trials could extend the conclusions beyond the individual patient, and help to characterize a subset of responders to a specific treatment or clarify the heterogeneity of the disease. The basic principles of the different single subject trial designs are described. Advantages and limitations are reviewed with a special focus on published trials in functional gastrointestinal disorders. The single subject trial may be a valuable supplement to traditional drug treatment trials, either used as isolated trials in individual patients to determine optimal therapy, or in groups of patients to identify those with a uniform response to treatment. However, the lack of validation and reliability studies limits the value of the single subject trials presented so far.
authors.affiliation: Department of Medical Gastroenterology M, Glostrup University Hospital, DK-2600 Glostrup, Denmark.
authors.forename: L G
authors.initials: LG
authors.lastname: Madsen
authors.forename: Peter
authors.initials: P
authors.lastname: Bytzer
mesh_terms: D000897:Anti-Ulcer Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004334:Drug Administration Schedule; D005767:Gastrointestinal Diseases / Q000188:drug therapy*; D006801:Humans; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D000897:Anti-Ulcer Agents