Incidence of multiple sclerosis in Switzerland - results from the Swiss multiple sclerosis registry.

BACKGROUND

While data on multiple sclerosis (MS) prevalence are widely available, incidence data, crucial for understanding disease onset dynamics, are less frequently reported. This study aims to estimate MS incidence in Switzerland from 2017 to 2021 and characterize persons newly diagnosed with MS.

METHODS

The Swiss MS Registry is an ongoing longitudinal study in Switzerland. It has established an innovative methodology to assess MS epidemiology by integrating SMSR data with administrative data on reimbursement approvals for disease-modifying therapies and by use of a modified benchmark-multiplier method. We calculated overall, sex- and age-specific MS incidence (2017-2021) and described the demographic and clinical characteristics of newly diagnosed individuals.

RESULTS

The estimated annual MS incidence in Switzerland was 663 [95% simulation interval 617-711] cases, corresponding to an annual MS incidence of 7.7 [7.1-8.3] per 100,000 inhabitants. This equates to approximately two new MS diagnoses per day. Incidence remained stable throughout the study period. Peak incidence occurred in the 30 to 35-year age group for women and 35 to 40-year age group for men. Most individuals were diagnosed with relapsing-remitting MS (94.0%). Following diagnosis, 56.9% received oral therapy, 27.7% infusion therapy, and 15.4% injectable therapy.

CONCLUSION

Our study found stable MS incidence over five years, consistently higher in women than men. Most diagnoses occurred between ages 20-40, though new diagnoses among middle-aged individuals appear to be increasingly common.