Use of the Multiple Sclerosis Functional Composite to predict disability in relapsing MS

Objective: To determine whether the MS Functional Composite (MSFC) can pred ict future disease progression in patients with relapsing remitting MS (RR- MS). Background: The MSFC was recommended by the Clinical Outcomes Assessme nt Task Force of the National MS Society as a new clinical outcome measure for clinical trials. The MSFC, which contains a test of walking speed, arm dexterity, and cognitive function, is expressed as a single score on a cont inuous scale. It was thought to offer improved reliability and responsivene ss compared with traditional clinical MS outcome measures. The predictive v alue of MSFC scores in RR-MS has not been determined. Methods: The authors conducted a follow-up study of patients with PR-MS who participated in a ph ase III study of interferon beta -1a (AVONEX) to determine the predictive v alue of MSFC scores. MSFC scores were constructed from data obtained during the phase III trial. Patients were evaluated by neurologic and MRI examina tions after an average interval of 8.1 years from the start of the clinical trial. The relationships between MSFC scores during the clinical trial and follow-up status were determined. Results: MSFC scores from the phase III clinical trial strongly predicted clinical and MRI status at the follow-up visit. Baseline MSFC scores, and change in MSFC score over 2 years correlat ed with both disability status and the severity of whole brain atrophy at f ollow-up. There were also significant correlations between MSFC scores duri ng the clinical trial and patient-reported quality of life at follow-up. Th e correlation with whole brain atrophy at follow-up was stronger for baseli ne MSFC than for baseline EDSS. Conclusion: MSFC scores in patients with RR -MS predict the level of disability and extent of brain atrophy 6 to 8 year s later. MSFC scores may prove useful to assign prognosis, monitor patients during early stages of MS, and to assess treatment effects.