To describe disparities in multiple sclerosis (MS) disability outcomes in migrants to a universal healthcare context.

Socioeconomic determinants of MS outcomes have gained recognition, with racial and ethnic minorities in user-pays systems experiencing worse disability. However, evidence for disparities in universal healthcare settings is mixed. Sweden has a short migration history and comprehensive universal healthcare. We hypothesise that non-Nordic migrants may experience worse MS outcomes due to socioeconomic factors but not healthcare access.

We conducted a population-level cohort study using the Swedish MS Registry, linked to national administrative registries. We included individuals with onset of relapsing MS at working age between 2001-2015, and residing in Sweden prior to onset. The primary exposure was birthplace, categorised as Nordic, Western (Europe, excluding Nordic countries/North America), and Non-Western (Asia, Africa, South America). Outcomes were clinical and work disability, measured as time to confirmed Expanded Disability Status Score (EDSS) 3 and disability pension use. Covariates included onset age, sex, premorbid socioeconomic status (education, individual and household income), and healthcare quality indicators (onset-to-diagnosis and diagnosis-to-treatment times).

Of 6005 participants, 5482 were Nordic-born, 250 migrated from Western regions, and 273 from Non-Western regions. Non-Western migrants had younger onset age (mean(SD) 34.1(7.5) vs 37.9(9.5)), higher male proportion (39.6% vs 29.7%), and lower median income (USD 8330 vs 20761). Diagnosis and treatment times did not differ significantly. Adjusting for age, sex and calendar year, non-Western migrants had higher hazard for work disability (aHR 1.41, 95%CI 1.03-1.93) compared to Nordic-born people. Both Western and Non-Western migrants had a higher hazard of reaching EDSS 3 (aHR 1.72, 95%CI 1.13-2.64; aHR 1.98, 95%CI 1.30-3.01). Estimates became nonsignificant when adjusted for socioeconomic indices and baseline EDSS.

Adverse disability outcomes in non-Western migrants to Sweden may be driven by socioeconomic but not healthcare disparities.