Effect of time to initiation and dose of methylprednisolone on outcome in multiple sclerosis‐related optic neuritis

Abstract Objectives It is known that the benefit of intravenous methylprednisolone (IVMP) in multiple sclerosis‐related optic neuritis (MS‐ON) is limited to an accelerated recovery. We aimed to evaluate the impact of time from symptoms onset to IVMP initiation and of IVMP dose on visual recovery among people with MS‐ON. Methods A retrospective cohort study of MS‐ON was undertaken. The associations between time from symptoms onset to IVMP as well as dose of IVMP and best‐corrected visual acuity (BCVA) improvement after 6–12 mo were analyzed. Results Sixty‐one events of ON from 61 patients were included (Age: 32 ± 13, Female: 46 [75%]). ON was the initial presentation of MS for 45 (74%) participants. The mean time from symptoms onset to initiation of IVMP was 5.8 ± 4.6 d. Twenty‐eight episodes (46%) were treated with 3 g and 33 episodes (54%) were treated with 4.5 g IVMP. The proportion of events with complete recovery of BCVA was similar between those who were treated up to 3 d, 4 to 7 or ≥8 d from onset (46%, 74%, 58%, respectively ( χ 2 (2) = 3.9, P = .14). Complete recovery of visual acuity was achieved in 71% and 49% of events treated with 3 and 4.5 g IVMP, respectively ( χ 2 (1) = 3.3, P = .07). On multivariate analysis, only nadir visual acuity predicted incomplete recovery of BCVA (odds ratio [OR] = 2.02; P = .05); IVMP timing and dose did not. Conclusion While intravenous corticosteroids remain the mainstay of treatment, increasing the dose or starting treatment earlier does not seem to improve long‐term recovery from MS‐ON. A substantial proportion of people with MS‐ON remain with residual impairment of BCVA, highlighting the need for better treatments.