Quality of life is decreased in persons with relapsing-remitting multiple sclerosis experiencing progression independent of relapse activity.

Background: Reduced quality of life (QoL) is an early feature of multiple sclerosis (MS). The effect of progression independent of relapse activity (PIRA) on QoL is poorly investigated.

Objective: To assess the impact of PIRA on QoL using patient-reported outcome measures (PROMs).

Methods: In a prospective observational study, 125 newly diagnosed persons with relapsing-remitting MS (PwRRMS) were assessed over 5 years with: EuroQoL-5-Dimension-3-level (EQ-5D-3L), EQ-visual-analogous-scale (EQ-VAS) and 29-item-MS-Impact-Scale (MSIS-29). PwRRMS were dichotomized: PIRA (worsening of expanded disability status scale (EDSS), timed-25-foot-walk or 9-hole-peg-test, independent of relapses) versus non-PIRA. PwRRMS were compared at baseline, year 5 (y5) and delta values (baseline scores subtracted from y5 scores) and annually using linear-mixed-effects-models.

Results: At y5, 19.2% had PIRA. PIRA versus non-PIRA PwRRMS were older (p < 0.001). At y5 PIRA PwRRMS had lower EQ-5D-3L (p = 0.001), higher MSIS-29-PHYS (p < 0.001), delta values showed lower EQ-5D-3L (p < 0.001) and EQ-VAS (p = 0.010), higher MSIS-29-PHYS (p = 0.004) and MSIS-29-PSYCH (p = 0.036). Linear-mixed-effects-models showed that, compared to PIRA, non-PIRA PwRRMS had an improvement in QoL: EQ-5D-3L: β = 0.039, p < 0.001; EQ-VAS: β = 2.401, p < 0.001; MSIS-29-PHYS: β = -0.107, p < 0.001; MSIS-29-PSYCH, β = -0.115, p < 0.001, during the 5-year study period.

Conclusions: Deteriorating QoL in the early course of relapsing-remitting multiple sclerosis (RRMS) is strongly associated with PIRA. Our results suggest that QoL PROMs should be monitored and recognized as an important aspect of progression.