European validation of a standardized clinical description of multiple sclerosis

Objectives The EDMUS system is a clinical database specifically tailored to the description of multiple sclerosis (MS). The EVALUED (Evaluation of the EDMUS system) study is an European project with two objectives: 1) to assess the inter-examiner reliability of the whole EDMUS system; 2) to validate the EDMUS-Grading Scale (EGS),which is a simplified version of the Kurtzke Disability Status Scale (DSS). Methods The protocol included 12 neurologists working in pairs within six European centres (Bari, Basel, Florence, London, Lyon, Wurzburg). They assessed independently 30 MS patients in their centre, filling in the EDMUS forms. The reliability of the system was assessed on selected key items in the history of the MS onset, the clinical course and the disease course classification. The clinical examination of the patients permitted an assessment of the Kurtzke Expanded Disability Status Scale (EDSS) and the EGS. Level of agreement was measured in terms of kappa and weighted kappa indexes whenever appropriate. Results The study included 180 patients with definite or probable MS of whom 37% were males. Age was 35.8+/-9.6 years (mean +/-SD), disease duration 7.8+/-5.7 years, and mean EDSS score 4.1+/-2.2. The disease course was relapsing-remitting in 67%, secondary progressive in 22%, and progressive from disease onset in 11%. For key items of the history, the inter-examiner reliability level ranged from moderate to excellent. Concerning the disability scales, perfect agreement was reached in 59 % for EDSS and 78% for EGS. The close correlation and linear association (r=0.94, p<0.0001) between both scales demonstrated EGS's construct validity. Conclusion The EDMUS system allows a consistent clinical description of MS using a common language. This standardized follow-up of MS patients is valuable especially in studies requiring a critical mass of informative patients.