Quality of life among injectable and oral disease-modifying therapy users in the Pacific Northwest Multiple Sclerosis Registry

BACKGROUND: Nine oral disease-modifying therapies (DMTs) have been approved for the treatment of multiple sclerosis (MS) in the United States. Few studies have examined self-reported quality of life (QoL) and functional status outcomes among patients who switch to oral medications from injectable MS therapies. This study compares self-reported QoL and disability status between participants switching from injectable to oral DMTs, to those who stay on injectable DMTs continuously for the same time period. METHODS: Longitudinal data were assessed from relapsing MS participants in the Pacific Northwest MS Registry completing a minimum of two surveys between 2012 and 2018 with a maximum of 36 months between surveys. Stayers were defined as those who remained on injectable DMTs continuously from Time 1 to Time 2; switchers were those who switched from injectable to either fingolimod, teriflunomide or dimethyl fumarate during the same time interval. Outcomes of interest were physical and psychological QoL, measured by the Multiple Sclerosis Impact Scale (MSIS-29), and disability, measured by the Patient Determined Disease Steps (PDDS). To analyze the effect of switching to oral DMT on outcomes at Time 2, a one-to-two propensity score matching (PSM) was used to match switchers to stayers. Outcomes at Time 2 were analyzed using paired t-test for QoL scores, and Stuart Maxwell test for PDDS as a categorical variable. RESULTS: Among 2385 participants who returned consecutive yearly surveys, 413 met the inclusion criteria for stayers and 66 for switchers. After one-to-two PSM, 124 stayers were matched to 62 switchers. Paired t-test showed no differences between switchers and stayers for physical (mean difference: − 0.41; [95% confidence interval CI: − 3.3-2.4]; p = 0.78) or psychological (mean difference: − 0.23; [95% CI, − 1.6- 1.1]; p = 0.74) QoL. Additionally, no differences were seen between switchers and stayers in self-reported disability status. CONCLUSIONS: MS registry participants who switched to an oral DMT from injectable showed no significant differences in QoL or self-reported disability status compared to those remaining on injectable DMT continuously in the same time period. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12883-020-02016-4.