title: [Responsiveness of the Expanded Disability Status Scale (EDSS) to disease progression and therapeutic intervention in progressive forms of multiple sclerosis].
abstract: BACKGROUND
  The standard approach in relapsing forms of multiple sclerosis (MS) has been to measure therapeutic effects on clinical exacerbations and physical disability as determined by the Expanded Disability Status Scale (EDSS). However, measuring clinical relapses is not a viable option in the progressive forms of MS because of their low frequency. Therefore, the standard approach in clinical trials of progressive forms of MS has been to use the EDSS as primary outcome measure.
  
  
  METHODS
  We examined the responsiveness of the EDSS to disease progression and treatment effects in the context of clinical trials of secondary progressive (SPMS) and primary progressive (PPMS) MS and compared it to the three functional tasks of the Multiple Sclerosis Functional Composite (MSFC): the Timed 25 Foot Walk (T25FW), the 9 Hole PEG (9HP), and the Paced Auditory Serial Attention Test (PASAT).
  
  
  RESULTS
  The effect size of the EDSS after two years on placebo was only 0.2-0.3 in both SPMS and PPMS, similar to the 9HP and the PASAT. In contrast, the effect size of the T25FW was much greater and driven to a large extent by subjects who could not complete the task.
  
  
  CONCLUSIONS
  The EDSS shows poor responsiveness to both disease progression and treatment effects in SPMS and PPMS. The use of alternative primary outcome measures is recommended for therapeutic trials of progressive MS.
authors.affiliation: Biogen Idec, Cambridge, MA 02142, USA. diego.cadavid@biogenidec.com
authors.forename: Diego
authors.initials: D
authors.lastname: Cadavid
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Tang
authors.forename: Gilmore
authors.initials: G
authors.lastname: O'Neill
mesh_terms: D002986:Clinical Trials as Topic; D004185:Disability Evaluation; D018450:Disease Progression; D006801:Humans; D020528:Multiple Sclerosis, Chronic Progressive / Q000503:physiopathology / Q000628:therapy; D009483:Neuropsychological Tests; D010919:Placebos; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D010919:Placebos