Longitudinal changes in social functioning in mildly disabled patients with relapsing-remitting multiple sclerosis receiving subcutaneous interferon β-1a: results from the COGIMUS (COGnitive Impairment in MUltiple Sclerosis) study (II).

PURPOSE: To report longitudinal changes in and explore the influence of cognition on social functioning in mildly disabled patients with relapsing-remitting multiple sclerosis (RRMS). METHODS: Italian patients (18-50 years) with RRMS and Expanded Disability Status Scale (EDSS) score ≤4.0 were assigned to interferon β-1a, 44 or 22 μg subcutaneously three times weekly, and underwent annual assessments for social functioning (Environmental Status Scale [ESS]) over 3 years. RESULTS: Baseline total ESS score did not differ between patients with and without cognitive impairment (P = 0.505). Total ESS score remained low (<2.0) and stable over 3 years in the whole study population, but worsened slightly when assessed by assigned treatment or treatment and baseline cognitive status (both P = 0.004), driven mostly by changes in the 'transportation' and 'financial/economic status' subscales. The strongest independent predictor of worsening ESS score was baseline EDSS score. Test-retest analyses confirmed that total ESS score and most subscales changed little over 3 years. CONCLUSION: ESS scores remained low and changed minimally over 3 years, reflecting the mild physical disability and good cognitive performance in this patient population. Determining the influence of cognitive function and treatment on longitudinal changes in social functioning requires further studies.