Abstract
BACKGROUND: The concept of benign multiple sclerosis (MS) is a matter of debate. In most definitions, only the Expanded Disability Status Scale (EDSS) score and disease duration are considered, although other factors may influence a patient's disability. The aims of this study were to evaluate the percentage of patients with benign MS in our cohort and to determine the proportion of these patients who remained benign after 20 and 30 years of disease evolution. Clinical and demographic variables related to this outcome were investigated. METHODS: Patients fulfilling the criteria for benign MS (EDSS < 3.0 and at least 10 years of MS evolution) were selected from a hospital-based series and followed up prospectively. The EDSS was assessed after 20 and 30 years of MS evolution. Clinical and radiological variables were evaluated. Fatigue, depression and cognition tests were performed. RESULTS: Eighty-two of the 485 patients evaluated in 1996 fulfilled the criteria for benign MS and were selected. In 51 of the 68 (75%) patients evaluated in 2006, the EDSS score continued to be ≤ 3. In 2016, 35 out of 58 (60%) patients continued to have an EDSS score ≤ 3. None of the clinical variables could predict persistence in the benign group. Eighteen of the 35 benign MS patients completed the questionnaires after 30 years. Fifty percent of them reported fatigue, 22% depression, and 83% had cognitive impairment. CONCLUSION: The majority of MS patients maintained a benign status even after 30 years of disease evolution. However, cognitive impairment in this group is notable.