Can the Expanded Disability Status Scale be assessed by telephone?

Abstract

Information from patients who are unable to continue their visits to a study centre may be of major importance for the interpretatio n of results in multiple sclerosis (MS) clinical trials. To validate a questionnaire based on the Expanded Disability Status Scale (EDSS), patients in five different European centres were assessed independently by pairs of trained EDSS raters, first by telepho ne interview and a few days later by standardized neurological examination. Seventy women and 40 men with an average age of 43.7 years (range 19 -74 years) were included in the study. Mean EDSS score at the last visit was 4.5 (0 -9). EDSS assessment by telepho ne was highly correlated with the EDSS determined by physical examination (Pearson’s correlation coefficient -0.95). A n intraclass correlation coefficient (IC C) of 94.8% was found for the total sample; 77.6% and 86%, respectively, for patients with EDSSB-4.5 (n -46) and \-4.5 (n -64). Kappa values for full agreement were 0.48; for variation by -0.5 steps and -1.0 steps, 0.79 and 0.90, respectively. Best agreement could be found in higher EDSS scores, where assessment by telepho ne interview might be needed most. The telepho ne questionnaire is a valid tool to assess EDSS score in cases where the patient is unable to continue visiting a study centre or in long-term follow-up of trial participants.