REPORT FROM ECTRIMS – BARCELONA, SPAIN – OCTOBER 7-10, 2015 – Benign MS is typically defined as EDSS < 3 at 10-15 years post-diagnosis, and there is considerable debate about how benign the disease course really is if long-term cognitive as well as physical disability is taken into account.

An analysis of the Swedish MS registry examined the long-term outcomes of patients with initially benign MS (Manouchehrinia et al. ECTRIMS 2015; abstract EP1378). Overall, 19.2% of patients had an initially benign course. Patients were more likely to be female, have a relapsing onset, be younger at diagnosis (mean 29.1 years), and have a lower EDSS score at first assessment (EDSS 1.8). The estimated median age at EDSS 3.0, 4.0 and 6.0 was 60 years, 75.1 years and 79.3 years respectively for the benign cohort, compared to 42 years, 52.8 years and 57.8 years respectively for the non-benign group. A total of 28% of initially benign MS patients progressed to SPMS (median age 66.5 years) compared to 39% of non-benign MS (median age 55.3 years), suggesting that about 14% of MS patients overall may have a benign course with respect to physical disability. The authors concluded that defining benign MS as EDSS < 3.0 at 15 years post-diagnosis does identify a population of patients with a significantly slower rate of worsening MS, and that time to EDSS 3.0 may be useful to predict future disability progression.

A University of Ottawa/University of Trieste study also examined long-term outcomes of patients with benign MS (Sartori et al. ECTRIMS 2015; abstract P770). Benign MS was defined as EDSS < 3.0 at 10 years from onset of first symptoms. At 20 years post-diagnosis, 66.3% of initially benign patients remained benign. Favourable prognostic factors were female sex, EDSS score < 1 at 10 years and only sensory symptoms at onset. Poor prognostic factors were EDSS >2 and only motor symptoms at onset. If benign MS was defined as EDSS score < 1 at 10 years, 81.6% of patients remained benign at 20 years post-diagnosis; this definition predicted a benign course with greater than 80% specificity. The authors suggested that a more strict definition of benign MS – either EDSS < 2 or even < 1 at 10 years – should be employed since more patients meeting this criterion are likely to remain benign a decade later.

Reviewer: Dr. Daniel Selchen, Head of Neurology, St. Michael’s Hospital, Toronto, Canada