THE EFFECT OF CORTICOSTEROIDS FOR ACUTE OPTIC NEURITIS ON THE SUBSEQUENT DEVELOPMENT OF MULTIPLE-SCLEROSIS

Background. Optic neuritis is often the first clinical manifestation o f multiple sclerosis, but little is known about the effect of corticos teroid treatment for optic neuritis on the subsequent risk of multiple sclerosis. Methods. We conducted a multicenter study in which 389 pat ients with acute optic neuritis (and without known multiple sclerosis) were randomly assigned to receive intravenous methylprednisolone (250 mg every six hours) for 3 days followed by oral prednisone (1 mg per kilogram of body weight) for 11 days, oral prednisone (1 mg per kilogr am) alone for 14 days, or placebo for 14 days. Neurologic status was a ssessed over a period of two to four years. The patients in the first group were hospitalized for three days; the others were treated as out patients. Results. Definite multiple sclerosis developed within the fi rst two years in 7.5 percent of the intravenous-methylprednisolone gro up (134 patients), 14.7 percent of the oral-prednisone group (129 pati ents), and 1 6.7 percent of the placebo group (126 patients). The adju sted rate ratio for the development of definite multiple sclerosis wit hin two years in the intravenous-methylprednisolone group was 0.34 (95 percent confidence interval, 0.16 to 0.74) as compared with the place bo group and 0.38 (95 percent confidence interval, 0.17 to 0.83) as co mpared with the oral-prednisone group. The beneficial effect of the in travenous-steroid regimen appeared to lessen after the first two years of follow-up. Signal abnormalities on magnetic resonance imaging (MRI ) of the brain were a strong indication of risk for the development of definite multiple sclerosis (adjusted rate ratio in patients with thr ee or more lesions, 5.53; 95 percent confidence interval, 2.41 to 12.6 6). The beneficial effect of treatment was most apparent in patients w ith abnormal MRI scans at entry. Conclusions. In patients with acute o ptic neuritis, treatment with a three-day course of high-dose intraven ous methylprednisolone (followed by a short course of prednisone) redu ces the rate of development of multiple sclerosis over a two-year peri od.