title: Minimal clinically important difference, low disease activity state, and patient acceptable symptom state: methodological issues.
abstract: The importance of determining a minimal clinically important difference (MCID) and a low disease activity state (LDAS) as treatment targets in clinical trials no longer needs to be demonstrated. However, many methodological issues remain: whether these thresholds should be defined for each criterion or for composite criteria, whether there is a difference between the LDAS and patient acceptable symptom state (PASS), how to determine these thresholds (i.e., the wording of the questions and the statistical approach), and whether there are confounding factors in their evaluation. We consider these methodological issues and discuss their impact. Methods to determine the thresholds must be standardized, and recommendations could be endorsed by an OMERACT module. Threshold values for the MCID and LDAS should be determined according to data-driven and experts' opinions and approaches.
authors.affiliation: Département d'Epidémiologie, Biostatistique et Recherche Clinique, Groupe Hospitalier Bichat-Claude Bernard (AP-HP), INSERM U738, Faculté Xavier Bichat (Université Paris 7), Paris, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Tubach
authors.forename: George A
authors.initials: GA
authors.lastname: Wells
authors.forename: Philippe
authors.initials: P
authors.lastname: Ravaud
authors.forename: Maxime
authors.initials: M
authors.lastname: Dougados
mesh_terms: D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000503:physiopathology*; D002986:Clinical Trials as Topic / Q000379:methods*; D018450:Disease Progression; D006305:Health Status Indicators; D006801:Humans; D017063:Outcome Assessment, Health Care / Q000379:methods*; D017060:Patient Satisfaction; D012219:Rheumatology / Q000379:methods*