Trajectories of disposable income among people of working ages diagnosed with multiple sclerosis: a nationwide register-based cohort study in Sweden 7 years before to 4 years after diagnosis with a population-based reference group

ObjectivesTo describe how disposable income (DI) and three main components changed, and analyse whether DI development differed from working-aged people with multiple sclerosis (MS) to a reference group from 7 years before to 4 years after diagnosis in Sweden.DesignPopulation-based cohort study, 12-year follow-up (7 years before to 4 years after diagnosis).SettingSwedish working-age population with microdata linked from two nationwide registers.ParticipantsResidents diagnosed with MS in 2009 aged 25–59 years (n=785), and references without MS (n=7847) randomly selected with stratified matching (sex, age, education and country of birth).Primary and secondary outcome measuresDI was defined as the annual after tax sum of incomes (earnings and benefits) to measure individual economic welfare. Three main components of DI were analysed as annual sums: earnings, sickness absence benefits and disability pension benefits.ResultsWe found no differences in mean annual DI between people with and without MS by independent t-tests (p values between 0.15 and 0.96). Differences were found for all studied components of DI from diagnosis year by independent t-tests, for example, in the final study year (2013): earnings (−64 867 Swedish Krona (SEK); 95% CI−79 203 to −50 528); sickness absence benefits (13 330 SEK; 95% CI 10 042 to 16 500); and disability pension benefits (21 360 SEK; 95% CI 17 380 to 25 350). A generalised estimating equation evaluated DI trajectory development between people with and without MS to find both trajectories developed in parallel, both before (−4039 SEK; 95% CI −10 536 to 2458) and after (−781 SEK; 95% CI −6988 to 5360) diagnosis.ConclusionsThe key finding of parallel DI trajectory development between working-aged MS and references suggests minimal economic impact within the first 4 years of diagnosis. The Swedish welfare system was responsive to the observed reductions in earnings around MS diagnosis through balancing DI with morbidity-related benefits. Future decreases in economic welfare may be experienced as the disease progresses, although thorough investigation with future studies of modern cohorts are required.