Comparison of the Kurtkze Expanded Disability Status Scale and the Functional Independence Measure: measures of multiple sclerosis-related disability

Background: Multiple sclerosis (MS) is a disease which has a variable clinical presentation followed by a variable clinical course. Therefore, accuracy of clinical rating scales to measure disability at initial clinical presentation and during follow-up visits is essential to accurately capture the variability inherent in this disease. This is particularly vital when attempting to identify the efficacy of interventions. Objective: This observational study in veterans with MS compared the Kurtkze Expanded Disability Status Scale (EDSS) and the Total Functional Independence Measure (TFIM) scale as measures of MS-related disability. Methods: We retrospectively reviewed the electronic charts of 76 veterans with MS who are regularly followed in our VA MS clinic. Local Institutional Review Board approval was obtained for the protocol. Data were analyzed using SAS (SAS System for Windows, version 9.2, SAS Institute Inc., Cary, NC, USA). Chi-square and Fisher exact tests were used to assess categorical variables. Kruskal-Wallis tests evaluated the relationships between MS types [relapsing-remitting MS (RR), secondary progressive MS (SP), primary progressive MS (PP) and clinical isolated syndrome (CIS)] and the initial TFIM, EDSS and Impairment Index (II) scores. Results: The EDSS score accurately measured MS-related impairment at initial evaluation and follow-up relative to an II. However, the EDSS score did not change over time, compared to the TFIM suggesting reduced sensitivity of the EDSS for detecting change in MS-related disability over time. Conclusions: This suggests TFIM scale is a more sensitive measure of MS-related disability than EDSS for use in future MS clinical trials.