Interferon-Β Therapy in Multiple Sclerosis Patients: Is Response Age Dependent

Abstract

The onset of Multiple sclerosis (MS) is usually between 20 and 40 years and in those patients, beta-interferons reduce relapse frequency in a rate of 30%. The purpose of this study was to compare the therapeutical response to IFN beta in young versus older MS patients. Multiple sclerosis patients with onset of symptoms older 40 were described as older age-onset MS (OAOMS) and the patients with onset of symptoms lower than 20 years were described as a young-onset MS (YOMS). Eighty-five YOMS patients and 22 OAOMS patients were enrolled from 1997 to 2007 and medical records for each patient were reviewed. Individuals with relapse rates of more than 1/year, who fail in reducing their attack rates and/or deterioration of disability, were described as evidence for lack of therapeutic response. In the YOMS group, 70,6% of patients were responder. This ratio were 59% in OAOMS group with no statistically difference. Female to male ratio was 2.15:1 in young patients and 3.4:1 in older patients. Older MS patients had a higher EDSS score at initiation of IFN beta therapy. In responder patients, female to male ratio was higher for older age onset patients (12/13 vs 36/60) (p < 0.05). Of nonresponder patients, female to male ratio was lower for older age onset patients (5/4 vs 22/3) (p < 0.05). Although progressive form of the disease is more common in late onset MS, literature is limited for the effect of onset age on IFN response. In this study, the response to IFN therapy in young onset MS patients has been found similar to older age onset MS patients.