Change in quality of life in patients with relapsing–remitting multiple sclerosis over 2 years in relation to other clinical parameters: results from a trial of intramuscular interferon β-1a

Abstract

Background: A randomized, placebo-controlled, multicenter study of weekly intramuscular injections of interferon beta-1a (IFNβ-1a) in relapsing–remitting multiple sclerosis included the Sickness Impact Profile (SIP), a validated measure of patient-reported quality of life (QoL). Objective: To demonstrate the impact of moderate to severe SIP disability at baseline and change in QoL as measured by SIP over 2 years in relation to other study parameters. Methods: In 158 patients, SIP scores were determined at baseline and 2 years. Scores were correlated with disease progression and treatment. Results: Patients who experienced disability progression, as defined by Expanded Disability Status Scale (EDSS) and annualized relapse rate, during the study demonstrated significant worsening in Physical SIP scores compared with patients who did not progress ( p = 0.031). In patients with low SIP scores, indicating moderate or severe disability at baseline, treatment with IFNβ-1a significantly improved Physical SIP subscores. Conclusions: Patients with disability progression defined using EDSS, the physician-derived primary outcome measure, had Physical SIP scores indicating worsening disability, validating the physician-derived primary outcome measure using patient self-report. Treatment with IFNβ-1a had beneficial effects on QoL in patients with worse SIP scores at baseline.