Prevalence and incidence of multiple sclerosis in the Netherlands

•Aligning with a global trend, prevalence rates of MS in the Netherlands have increased significantly over the last decennia and are estimated at 210 per 100,000 inhabitants.•MS incidence in the Netherlands remains stable at 7.1 cases per 100,000 person-years.•One-third of the MS cohort identified through primary care records was not documented in the hospital database, suggesting that a significant portion of MS patients may not be currently receiving specialized neurological care. This could be attributed to either a benign or advanced disease course, or from patients opting out of follow-up by a neurologist. The rising prevalence estimates of multiple sclerosis (MS) globally underscore the imperative for up-to-date epidemiological data specific to the Netherlands. Data from two Dutch healthcare databases (Nivel Primary Care Database and Vektis Database) comprising both general practices and hospital electronic health records in 2019 were combined to assess age- and sex-standardized MS prevalence and incidence estimates. Differences in prevalence estimates based on latitude and between primary versus secondary care records were examined. The age and sex-standardized prevalence estimate was 210.4 per 100,000 inhabitants. Incidence estimate of MS was 7.1 per 100,000 person-years within the year 2019. One-third of the MS cohort from primary care records was not documented in the hospital database over two consecutive years. Prevalence estimates were higher in northern areas versus southern areas (respectively 240.6 versus 208.3 per 100,000 inhabitants). Aligning results from different global regions, prevalence estimates of MS in the Netherlands have increased significantly over the last decennia, while incidence estimates are stable. The discrepancy between MS records within the primary and secondary care setting could indicate that a substantial proportion of Dutch patients with MS are not under specialized neurological care.