Adherence to self-administering interferon-β1a using RebiSmart® device in Mexican patients with relapsing multiple sclerosis

Background: Adherence to disease-modifying therapies is determinant to attain maximal clinical benefit in multiple sclerosis (MS). RebiSmart® is an electronic auto-injector for subcutaneous delivery of interferon β-1a (INF-β1a) that monitors adherence by featuring a log of each drug administration for objective evaluation. The aim of this study was to assess long-term adherence to INF-β1a by using the RebiSmart® device in Mexican patients with relapsing MS. Methods: This is an observational multicenter study on patients with relapsing MS treated with INF-β1a subcutaneously delivered by the RebiSmart® device. Adherence was computed as the number of injections received during the study period divided by the number of injections scheduled and expressed as percent. Results: A total of 66 patients from 6 specialized MS centers were evaluated (45 females and 21 males, mean age 43.91±13.32 years). Mean adherence was 79.51±18% (median: 85.54%, range: 34.4–100%). During a median follow-up of 27.5 months (mean 33.36±29.39 months) the annualized relapse rate had a mean of 0.50±1.63. Mean initial EDSS was 1.90±1.52, and mean EDSS at the end of follow-up was 1.80±1.74. Compared with their counterparts, the mean number of relapses was significantly lower among patients with high (>80%) adherence (0.25±0.44 vs 0.67±92 relapses, respectively; P = 0.03). The proportion of relapse-free patients was 75.0% among patients with high adherence and 53.3% in low-compliant patients (P = 0.06). High adherence patients presented lower rates of EDSS worsening ≥1.0 at the end of treatment, as compared with low-compliant patients (11.1% vs 43.3%, respectively; P = 0.003). High schooling (>12 years) was the only predictor of a high adherence (OR: 2.97, 05% CI: 1.08–1.18; P = 0.03) and of being relapse-free during follow-up (OR: 3.22, 05% CI: 1.12–9.23; P = 0.03). Conclusion: Adherence to INF-β1a using RebiSmart® in this Mexican cohort with MS was moderate, but associated with low relapse rate and influenced by high schooling.