Long-term follow-up of benign multiple sclerosis in Hordaland County, Western Norway

To study the frequency of benign multiple sclerosis (MS) after 20 years disease duration and identify early clinical and demographic prognostic factors of a benign course.

A population-based cohort including all 230 MS patients with clinical disease onset during 1976-1986 in Hordaland County, Western Norway was followed up with clinical examination in 1995 and 2003. Benign MS was defined as an Expanded Disability Status Scale (EDSS) score

A relapsing-remitting disease course at onset, female gender, and younger age at onset were significantly associated with a benign course, but could only explain 23.0% of the variation in the benign course. A low annual relapse rate was also associated with a benign course. When including this variable in the model, 42.3% of the variation could be explained. The number of benign MS cases decreased significantly from 37.6% in 1995 to 24.2% in 2003.

Benign MS is frequently a temporary condition. Only a small part of the variation in the long-term benign course could be explained by clinical data present in the early phase of the disease. With several new emerging therapies in MS, the need for more reliable prognostic factors is increasing, to improve and individualize patient treatment.