Treatment of early-onset multiple sclerosis with intramuscular interferonβ-1a: long-term results
OBJECTIVES To establish the prognostic role of clinical and demographic factors in a hospital-based cohort of MS patients categorized by age at clinical onset and clinical course. METHODS Eighty-three patients with MS had a clinical onset of the disease in childhood (age <16 years; early-onset MS [EOMS]) and 710 in adult age (between 16 and 65 years; adult-onset MS [AOMS]). Patients were followed for a mean period of observation of 5 years. Univariate and multivariate analyses of clinical and demographic predictors for rapid progression and disability were performed using a stepwise Cox regression model with time-dependent covariates. RESULTS In EOMS, the Expanded Disability Status Scale (EDSS) evaluated at last clinical examination was lower than in AOMS, despite a longer disease duration. The probability to reach growth disability and progression was significantly lower in EOMS than in AOMS. Median times to reach EDSS score of 4 and secondary progression were longer in EOMS than in AOMS, but the age at both endpoints was significantly lower in EOMS. In EOMS and AOMS, an irreversible disability was related to a secondary progressive course, a sphincteric system involvement at onset, and an older age at onset (in EOMS only for the group >14 years); in AOMS, other unfavorable factors were a pyramidal involvement at onset and a high relapse frequency in the first 2 years. The risk of entering secondary progression was significantly influenced by a high number of relapses in EOMS and by a higher age at onset and a short interattack interval in AOMS. CONCLUSION A slower rate of progression of disease characterized EOMS patients, suggesting more plasticity to recover in developing CNS, but the early clinical manifestation cannot be considered a positive prognostic factor.