Age differences in trajectories of self-rated health of young people with Multiple Sclerosis

Background: Recent evidence has suggested an existence of a multiple sclerosis (MS) prodrome. Hence, some young adults with MS are very likely to have had symptoms in childhood or adolescence. It is, therefore, reasonable to assume that people aged under 25 years with MS might have had pediatric-onset. In contrast, young people aged between 26 and 35 are less likely to have had pediatric-onset. Contrasting these two groups of people could lead to valuable information about the impact of MS over time. The purpose of this study is to characterize how self-rated health (SRH) in young people with MS changed over time and to estimate the extent to which SRH differs between age groups (18 to 25 years and 26 to 35 years) and sex.

Methods: This study utilized placebo arm data from the Multiple Sclerosis Outcome Assessment Consortium database. Responses to the RAND-36 SRH item of 393 participants were included. Group-based trajectory models (GBTM) were used to identify patterns of change over two years. Ordinal regression was performed to estimate whether these trajectory groups differed by age group, sex, and relapse event.

Results: Results of GBTM showed that all groups were stable over time except one progressing from a rating of "very good" to "excellent". Posterior probabilities showed that 35% of people consistently rated their health "very good or excellent" and 2% consistently rated their health as "poor". Health perceptions differed across age groups (β = 0.5, OR: 1.7 CI: 1.1, 2.6) but not sex (β = -0.1, OR: 0.9 CI: 0.6 1.3). Compared to the younger group, people aged 26 to 35 years are 1.7 times more likely to rate their health poorer. People with relapses are also 2.2 times more likely to rate their health poorer (β = 0.8, OR: 2.2 CI: 1.5, 3.2).

Conclusion: Trajectories of SRH of young people with MS were relatively stable. In the absence of drug treatment, people in the younger group (<25 years) rated their health better than those in a slightly older group which is consistent with lower disability.