To develop a claims-based proxy for the EDSS for estimating the disability related to MS.

The Expanded Disability Status Scale (EDSS) is a method of quantifying disability in multiple sclerosis (MS) and monitoring its accumulation over time. EDSS assessments are not observable in claims data as no ICD-10 code exist.

44 MS-related symptoms were classified into mild, moderate and severe across 7 functional systems, based on their impact on disability, quality of life and depending on the type of therapy they were treated with. Medical claims from a German statutory health insurance were mapped into a claims-based proxy for the EDSS. The proxy was computed for cohorts of RRMS and other MS (non-RRMS) patients identified through sub-codes in the German modification of the ICD-10. The EDSS was computed in the year before and after first observed MS diagnosis between 01/07/2016 and 30/06/2017. Descriptive statistics were reported in the two cohorts for baseline and follow-up periods by gender and age.

1,276 RRMS (75% females; median age=46) and 1,541 non-RRMS patients (69% females; median age=60) were identified. RRMS patients had a lower mean EDSS score (baseline: 2.8; follow-up: 3.0) compared to non-RRMS patients (baseline: 5.0; follow-up: 5.1). The most prevalent symptoms at baseline and during follow-up were in the cerebral functional system (41.8% and 44.4%) for RRMS patients, and in the pyramidal functional system (54.4% and 56.6%) for non-RRMS patients. Higher mean EDSS score was seen among females in RRMS but not in non-RRMS males. For both RRMS and non-RRMS patients, the EDSS score among patients was higher in the over 60-year-old than in younger age groups.

While the validation of the algorithm is warranted for future research, results are aligned with epidemiology and the proxy EDSS can help investigate disease progression in real-world evidence studies.