Delayed diagnosis of multiple sclerosis: prevalence, causes and prognostic significance

   Timely diagnosis of multiple sclerosis (MS) and early initiation of pathogenetic therapy are associated with a more favourable course of the disease and a lower degree of disability.

   Objective: to analyse the structure, causes and consequences of late diagnosis of MS among patients at the Russian Centre of Neurology and Neuroscience.

   Material and methods. The study included 125 patients with MS, clinically isolated syndrome (CIS) and radiologically isolated syndrome (RIS) who were referred for outpatient admission at the Russian Centre of Neurology and Neuroscience between October 2023 and March 2025. The duration of diagnosis and the time from disease onset to diagnosis, the reasons for delayed diagnosis and the correlation between delayed diagnosis and the degree of disability according to the Expanded Disability Status Scale (Expanded Disability Status Scale, EDSS) were determined, and a comparison was made with data from the Russian registry of patients with MS and data from foreign studies.

   Results. The median time to diagnosis was 10.0 [2.0; 42.8] months, and the mean time was 38.3 ± 69.7 months. The mean time between onset and brain magnetic resonance imaging was 29.9 ± 70.8 months, with a median of 5.0 [0.0; 23.8]. The frequency of delayed diagnosis of MS was 67.7 % (65/96). The mean EDSS score at the time of diagnosis was 2.6 ± 1.2 points. A statistically significant direct correlation was established between late diagnosis and a higher degree of disability on the EDSS scale (ρ = 0.331; p = 0.001).

   Conclusion. Late diagnosis of MS is associated with a higher degree of disability on the EDSS scale. The introduction of standard diagnostic deadlines for MS into clinical guidelines may help to reduce the frequency of delayed diagnosis and decrease the disability associated with late treatment initiation in patients.

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