Expanded disability status scale by phone BR: Brazilian Portuguese validation

Background: The Expanded Disability Status Scale (EDSS) is widely used and accepted by regulatory agencies for the assessment of neurological disability secondary to Multiple Sclerosis. The "Expanded Disability Status Scale (EDSS) by phone" was developed to be a patient-reported telephone-based alternative for the assessment of EDSS functional system scores when a physical examination is not possible. The scale has been validated in multiple languages; however, its reliability has not been assessed in Brazilian Portuguese. Methods: After cross-cultural translation and adaptation, 57 people with MS with a recent in-person visit (+/- 6 months) were invited to answer the EDSS by phone scale on two occasions, 15 days apart. The agreement between scales (in-person and telephone-based) and between telephone-based assessments was evaluated using intraclass correlation coefficients (ICC) for absolute agreement and weighted Kappa coefficients. Results: An excellent reliability was obtained for the agreement between the in-person and telephone assessments (ICC: 0.95, 95 %CI 0.92-0.97, Kappa: 0.83, 95 %CI 0.78-0.89) and between telephone-based assessments (ICC: 0.99, 95 %CI 0.98-0.99, Kappa: 0.93, 95 %CI 0.88-0.97). After stratification by disability level, the agreement between scales was less pronounced for subjects with an EDSS <= 4.0. Conclusion: this study offers evidence that supports the validity of the EDSS by phone questionnaire translated into Brazilian Portuguese, particularly for patients with higher EDSS scores.