A longitudinal study of quality of life and side effects in patients with multiple sclerosis treated with interferon beta-1a

In a 12-month follow-up study, we evaluated 27 patients (18 F and 9 M) with relapsing-remitting (RR) multiple sclerosis (MS), who had started treatment with interferon beta-1a (IFNβ-1a) (Avonex), 30 μg i.m. once weekly, 6-18 months (median 10 months) before study entry. Quality of life (QOL), disability, independence, cognitive performances, symptoms of depression and anxiety, and fatigue were assessed at baseline, 6 months and 12 months. The frequency and severity of the side effects of treatment, at hours 0-12, 13-48 and 49-168 after the injection, were self-reported weekly in a structured questionnaire. QOL did not change significantly during the follow-up. The percentage of patients who reported side effects after the injection of IFNβ-1a remained constant during the 52 weeks. The mean number of side effects increased significantly from the 6th to the 12th month. The general linear model analysis of variance disclosed significant changes over time for almost all side effects, but we did not find any correlation between QOL and number of side effects. In conclusion, 1-year treatment with IFNβ-1a did not significantly change patient's QOL. Disability progression correlated with patient's QOL. Side effects, which were mild, did not diminish over time, did not induce treatment discontinuation and did not interfere with QOL.