Objective: This study was undertaken to describe and compare disease course and prognosis of early (ie, disease onset before age 11 years) and late (ie, disease onset after age 11 years) onset pediatric multiple sclerosis.
Methods: Prospectively collected clinical information from Italian Multiple Sclerosis Register of 1993 pediatric multiple sclerosis patients, of whom 172 had early onset, was analyzed. Cox models adjusted for sex, baseline Expanded Disability Status Scale score, and disease-modifying treatments and stratified for diagnostic criteria adopted (Poser vs McDonald) were used to assess the risk of reaching irreversible Expanded Disability Status Scale scores of 3, 4, and 6, and conversion to secondary progressive phenotype in early versus late onset pediatric patients.