Aim of the study: To compare the demographic, clinical and laboratory characteristics of patients with multiple sclerosis (MS) analysed based on the age at which they were diagnosed.
Clinical rationale for the study: Most cases of MS are diagnosed between the ages of 20 and 40 years, but the clinical characteristics of patients with MS over this age range have rarely been studied.
Material and methods: 182 patients diagnosed with MS between 2000 and 2015 were divided into four groups by age at diagnosis: < 30 years (n = 62), 30-39 years (n = 54), 40-49 years (n = 27), and ≥ 50 years (n = 39). The demographic, clinical and laboratory features of each age group were investigated and between-groups comparisons analysed.
Results: There were no significant differences in the female-to-male ratio between groups, which was close to 3:1 in every group (p = 0.98). Motor symptoms were more common as the first manifestation of MS with increasing age (< 30: 19.3%; 30-39: 37.0%; 40-49: 44.4%; ≥ 50: 61.5%). Visual and sensory symptoms were responsible for nearly half of first manifestations in patients < 30 to 49, but affected a significantly lower proportion of patients in the oldest group (p = 0.01). Median (interquartile range [IQR]) Expanded Disability Status Scale at diagnosis was higher with advancing age (2 [1.5-3], 2.25 [1.5-3.5], 3 [2-3.5], and 3.5 [3-5]; p < 0.01). There was also a higher proportion of patients with progressive forms of the disease with age, especially primary progressive MS (0.0%, 3.7%, 14.8%, and 51.3%; p < 0.01). The median (IQR) time needed to confirm the diagnosis of MS became significantly longer as age increased (7 [2-25], 9 [2-32], 12 [6-58], and 26 [12-60] months; p < 0.01). In laboratory tests, significant differences were found only in the rate of post-contrast enhancement by magnetic resonance imaging, which was lower in the older age groups (63.2%, 50.0%, 31.6%, and 30.0%; p < 0.01).
Conclusions and clinical implications: Our study indicates significant differences in the demographic and clinical picture of MS depending on the age of the patient at diagnosis. Diagnostic delay in older patients is a common problem, and this study shows the features of later forms of MS to help inform neurologists and improve time to diagnosis.
Keywords: Multiple sclerosis; age at diagnosis; clinical differences; time from first symptoms to diagnosis.