RESUMEN
BACKGROUND: Few studies have analysed long-term effects of immunomodulatory disease modifying drugs (DMDs). OBJECTIVE: Assessment of the efficacy of DMDs on long-term evolution of multiple sclerosis, using a Bayesian approach to overcome methodological problems related to open-label studies. METHODS: MS patients from three different Italian multiple sclerosis centres were divided into subgroups according to the presence of treatment in their disease history before the endpoint, which was represented by secondary progression. Patients were stratified on the basis of the risk score BREMS (Bayesian risk estimate for multiple sclerosis), which is able to predict the unfavourable long-term evolution of MS at an early stage. RESULTS: We analysed data from 1178 patients with a relapsing form of multiple sclerosis at onset and at least 10 years of disease duration, treated (59%) or untreated with DMDs. The risk of secondary progression was significantly lower in patients treated with DMDs, regardless of the initial prognosis predicted by BREMS. CONCLUSIONS: DMDs significantly reduce the risk of multiple sclerosis progression both in patients with initial high-risk and patients with initial low-risk. These findings reinforce the role of DMDs in modifying the natural course of the disease, suggesting that they have a positive effect not only on the inflammatory but also on the neurodegenerative process. The study also confirms the capability of the BREMS score to predict MS evolution.