(191) Healthcare resource use (HRU) of patients with active relapsing multiple sclerosis (RMS) using data linkage between a phase IV study and the France's national health data system.

Background: The PRO-MSactive study is a phase IV study designed to evaluate the efficacy of ocrelizumab in active forms of relapsing multiple sclerosis (RMS). By complementing these clinical data with claims data from the French national health data system (SNDS), a global overview of the RMS burden can be obtained, by disability level.

Objectives: To describe the HRU of patients with active RMS in the two years prior to ocrelizumab initiation, according to Expanded Disability Status Scale (EDSS) score.

Methods: All patients followed for 48 weeks in the PRO-MSactive study, including RMS and secondary-progressive MS patients from July 2018 and July 2019, were selected. They were linked to an SNDS extraction, consisting in all patients with a MS between January 1, 2013 and December 31, 2020, identified through diagnoses (ICD-10 code G35, from hospitalisation discharges and chronic disease status), and an injection of ocrelizumab, using a deterministic approach. Only RMS patients with 5-year data history in the SNDS were included. HRU were described in the two years prior to ocrelizumab initiation, by 12 months period (n-1 and n-2), according to the EDSS score ( < 4 versus ≥ 4), for the following healthcare expenditure items: medications, medical visits, hospitalizations, medical devices, medical procedures, lab tests, sick leaves, disability pension and medical transports.

Results: Of the 371 patients included in the PRO-MSactive study and eligible to the linkage, 291 (78.4%) were linked to one of the 6,077 MS patients extracted from SNDS, of whom 257 patients (88.3%) with a RMS and a 5-year data history were included in this study (74.3% of females, mean age of 38.5 years). Most RMS patients were non-treatment-naïve (71.2%) and the most frequent treatment received prior to ocrelizumab initiation was fingolimod (27.3%). For all symptomatic treatment studied, the percentage of patients with a dispensation (except pain killers) and the mean number of dispensations (except antiepileptics and anticholinergics) were higher in patients with EDSS score ≥4, over n-1 and n-2 periods. The proportion of patients hospitalised increased between year n-2 and n-1 (from 26.5% to 65.4%) and was higher in those with a EDSS score ≥4 (43.5% vs. 23.6% in year n-2 and 76.1% vs. 63.2% in year n-1). The proportion of patients on sick leave also increased between year n-2 and n-1 (from 24.1% to 38.5%).

Conclusions: This burden of disease study is the first to combine clinical data from a phase IV study with claims data from SNDS. It allowed us to estimate the greater burden of disease of RMS patients with a higher level of disability (EDSS score ≥4) and to evaluate the increase in HRU associated with the disease activity the year before enrolling in the phase IV study.