Clinical instrument to retrospectively capture levels of EDSS

Background: The Expanded Disability Status Scale (EDSS), a common outcome measure in Multiple Sclerosis (MS), is obtained prospectively through a direct standardized evaluation. The objective of this study is to develop and validate an algorithm to derive EDSS scores from previous neurological clinical documentation. Methods: The algorithm utilizes data from the history, review of systems, and physical exam. EDSS scores formally obtained from research patients were compared to captured EDSS (c‐EDSS) scores. To test inter‐rater reliability, a second investigator captured scores from a subset of patients. Agreement between formal and c-EDSS scores was assessed using a weighted kappa. Clinical concordance was defined as a difference of one-step in EDSS (0.5) and functional system (1.0) scores. Results: Clinical documentation from 92 patients (EDSS range 0.0–8.5) was assessed. Substantial agreement between the c‐EDSS and formal EDSS (kappa 0.80; 95% CI 0.74–0.86) was observed. The mean difference between scores was 0.16. The clinical concordance was 78%. Near-perfect agreement was found between the two raters (kappa 0.89; 95% CI 0.84–0.95). The mean inter-rater difference in c-EDSS was 0.23. Conclusions: This algorithm reliably captures EDSS scores retrospectively with substantial correlation with formal EDSS and high inter‐rater agreement. This algorithm may have practical implications in clinic, MS research and clinical trials.