Beta interferons in clinically isolated syndromes: a meta-analysis.

Beta-interferon use in definite multiple sclerosis (MS) has been proven to modify clinical and magnetic resonance imaging outcome. We review and summarize the data of published double-blind, randomized clinical trials to assess, with a meta-analysis the safety and efficacy of beta-interferon on the occurrence of relapses in patients with a first clinical event suggestive of MS. After two years of follow-up, interferon beta decreased the risk of conversion to clinically definite MS 0.51[0.39-0.65], and delayed the time to diagnosis up to 367 days. Side-effects were mild and self limited. Our findings support the efficacy of early treatment with beta-interferon in reducing conversion to clinically defined MS in patients with clinically isolated syndromes.