Real-world annualized relapse rates from contemporary multiple sclerosis clinics in the UK: a retrospective multicentre cohort study.

Abstract

Background: Annualized relapse rate (ARR) is used as an outcome measure in multiple sclerosis (MS) clinical trials. Previous studies demonstrated that ARR has reduced in placebo groups between 1990 and 2012. This study aimed to estimate real-world ARRs from contemporary MS clinics in the UK, in order to improve the feasibility estimations for clinical trials and facilitate MS service planning.