Figure 1.

MS patients reaching the outcome (EDSS ≥ 6.0) or ending the follow-up before attaining it. Disease activity was defined as the occurrence of relapses or enhancing lesions on the MRI scan. Over a mean ± SD observation period of 6.3 ± 3.1 years, the majority of patients attained an EDSS ≥ 6.0, mainly in association with disease activity. The four groups defined by the attainment of the disability outcome in the presence or absence of disease activity are indicated as groups A, B, C and D.