Adherence to self-administering interferon-beta1a using RebiSmart(R) 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(R) is an electronic auto-injector for subcutaneous delivery of interferon beta-1a (INF-beta1a) 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-beta1a by using the RebiSmart(R) device in Mexican patients with relapsing MS. METHODS: This is an observational multicenter study on patients with relapsing MS treated with INF-beta1a subcutaneously delivered by the RebiSmart(R) 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-beta1a using RebiSmart(R) in this Mexican cohort with MS was moderate, but associated with low relapse rate and influenced by high schooling.