Specific clinical phenotypes in relapsing multiple sclerosis: The impact of relapses on long-term outcomes

- We identified specific phenotypes of MS according to relapse type and progression.
- Significance of attacks decreases over time; failure to recover is still important.
- Incomplete recovery from relapse significantly contributes to worsening in RRMS.
- Phenotypic patterns of MS may be important in evaluating treatment response.

ObjectiveThe impact of relapses on the disease course of relapsing MS remains to be determined. This study aims to identify and characterize clinical phenotypes of relapse onset MS in a longitudinally studied cohort.MethodsWe recorded the clinical course of MS during the first decade of disease, using five-year epochs. Patients were stratified as: no worsening due to relapse or secondary progression (type A), relapse with worsening seen without secondary progression (type B), secondary progression with no worsening due to relapse (type C), worsening due to relapses mixed with secondary progression (type D).ResultsOf 176 patients followed from diagnosis for 12.62±4.18 years, 93.2% (164/176) had increased disability in their first 5-year epoch of MS and 52.2% (72/138) in the next. The phenotypes significantly differed by EDSS change during each epoch (p<0.001), final confirmed MSSS (p≤0.002) and relapse rate (p<0.001). Type D fared worse than others by change in EDSS and MSSS.ConclusionWe identified multiple specific phenotypes of MS and temporal shifts between phenotypes according to relapse type and progression.