Secular trends in disease modifying treatment and expenditure in multiple sclerosis: A longitudinal population study in the north of Ireland.

ABSTRACT

BACKGROUND: The epidemiology of multiple sclerosis (MS) is important for planning disease modifying therapy (DMT). Secular changes in the use of DMT in MS can guide future service development. METHODS: A population study of the prevalence of multiple sclerosis was completed in the west of Northern Ireland - a defined geographic area making up the Western Health and Social Care Trust (WHSCT). The use, category and cost of DMT for the MS population in the WHSCT were measured over 11 years. RESULTS: The WHSCT had a recorded prevalence of MS of 238.4/100,000 (95%CI 221.5-256.5) in 2018. DMT use increased over threefold in 11 years. Four hundred and nine (57%) of 720 MS patients were taking a DMT by 2018. The annual expenditure of DMT drugs had increased sixfold over ten years to £5,301,198 in 2018 (using 2018 prices), reflecting both an increase in DMT use and a switch to more intensive DMTs. Younger MS patients were more likely to be taking a DMT (P<0.001). CONCLUSION: DMT use and cost have been increasing among the MS population in the Northern Ireland. There has been a temporal switch to more efficacious DMTs. Future research should monitor the cost-effectiveness and equity of treatment of MS patients.