LAUSR

BACKGROUND Differential treatment allocation may impact on clinical phenotype in MS and in turn upon quality of life (QoL). OBJECTIVES (a) Investigate the association between disease-modifying drugs (DMDs) use and relapse frequency, disability, clinically significant fatigue, and physical and mental health-related QoL among participants with MS residing in Australia and New Zealand (NZ); (b) assess whether these associations differed between Australia and NZ. METHODS Disability and fatigue were measured by PDDS and FSS, respectively. QoL was assessed by MSQOL-54. Associations were assessed by binomial and multinomial logistic regression, as appropriate. Multivariable models were adjusted for demographic and clinical covariates, as appropriate. RESULTS 837 participants (627 from Australia; 210 from NZ) were identified from an online cohort of people with MS. First- and second-generation DMD use was associated with higher adjusted-odds of fatigue and disability, though not with 12-month relapse number. DMD use was not independently associated with physical or mental QoL. The association of first-generation DMD use with moderate disability differed between nations, such that treatment was associated with lower odds in Australia but not in NZ; a similar but a small difference was found for severe disability. No differences were seen in the DMD association with relapse number, nor with fatigue or QoL, between Australia and NZ. CONCLUSION The differential treatment allocation associations in NZ are evident in the DMD-disability association, but there is no evidence that this treatment regimen has negative associations with fatigue, mood, or QoL.