Disposable Income Trajectories of Working-aged Individuals with Diagnosed Multiple Sclerosis

Objectives: The economic situation of individuals diagnosed with multiple sclerosis (MS) is under studied, with the levels and sources of incomes suggested to vary with socio-demographics. We aimed to describe the diversity of disposable income (DI) trajectories among working-aged individuals with incident MS, and investigate the associations of socio-demographic characteristics with identified trajectories.

Materials & Methods: A population-based cohort study of all 1528 individuals first diagnosed with MS in 2008-2009 when aged 25-59, with data linked from three nationwide Swedish registers. DI was defined as net earnings plus net income from benefits. Trajectories of mean annual DI from 7 years prior to 4 years after diagnosis were identified by group-based trajectory modelling. An individual's group membership was determined by individual model-fit estimates from a multinomial logit function. Chi-squared tests and multinomial logistic regressions estimated the associations between trajectory membership and socio-demographic (sex, age, education, birth country, type of living area and family situation) and work disability (sickness absence and disability pension) characteristics.

Results: Seven distinct DI trajectories were identified: two consistently low (50.7% of individuals); four increasing (39.0%); and one decreasing (10.3%). Socio-demographic and work disability characteristics were associated with trajectories; the increasing trajectories had older age-profiles and higher proportions of men, while university education was less common in the consistently low trajectories.

Conclusions: We identified high diversity in DI development within the cohort around MS diagnosis. Socio-demographic and work disability characteristics differed between the trajectories. This broader information of the economic situation is important to convey to patients.