The dilemma of benign multiple sclerosis: Can we predict the risk of losing the "benign status"? A 12-year follow-up study.

BACKGROUND: Definition of benign multiple sclerosis (BMS) remains controversial. Moreover, a sizeable proportion of classically defined BMS patients may be no longer benign (NLB) when re-assessed in the long-term. In a previous work, we found that after a five-year follow-up, a clinical score was able to identify patients at risk of losing their benign status. OBJECTIVES: In this 12-year reappraisal of the same cohort, we aimed at assessing the predictive value of the same score in the long-term. METHODS: After a mean follow-up of 12.6 + 0.4 years, patients still having an EDSS score <3.0 were classified as "still benign" (SB), whereas patients having an EDSS score ≥3.5 were defined as NLB. The predictive value of the mentioned score was re-assessed using survival analysis. RESULTS: By the end of the follow-up, 20 (32.8%) were classified as NLB. Patients were grouped on the basis of the above mentioned score. Patients with score 2-3 were at higher risk of NLB status at the follow-up (HR = 3.5; 95%CI 1.5-8.6; p = 0.005, accuracy = 70.5%). CONCLUSIONS: In patients with established BMS, prognostic prediction of longer-term disease course remains of critical value. In this study, a clinical score was able to predict disease evolution in the long term.