Exploratory Analysis of Predictors of Patient Adherence to Subcutaneous Interferon beta-1a in Multiple Sclerosis: TRACER Study

Expert Opin Drug Deliv. 2016 Jun;13(6):799-805. doi: 10.1517/17425247.2016.1158161. Epub 2016 Mar 12.


Objective: The TRACER multicenter retrospective study aimed to collect data on treatment adherence in a real-life setting, in order to identify predictors of adherence at baseline.

Methods: We recruited 384 relapsing-remitting (RR) multiple sclerosis patients with at least 12 months of use of RebiSmart®. This electronic device records the performed injections and assesses adherence as the percentage of 'not missing doses', through the connection to the iMed database. Subjects with at least 80% of completed doses at the 12 month of therapy were defined 'treatment adherents'.

Results: After 12 months, 89.3% of patients were adherent; 93.2% of patients aged 26-40 years at baseline were adherent (vs 79% of the ≤25 and 87.5% of the ≥41 year olds; p = 0.006). Furthermore, 90.5% of patients with a baseline Expanded Disability Status Scale (EDSS) score <4 showed ≥80% adherence (vs 71.4% in those with EDSS score ≥4; p = 0.016). Fifty-four percent of the patients who were not adherent after 3 months were also not adherent after 12 months (OR 16.8; CI 95%:7.1-39.8).

Conclusions: Patients aged 26-40 years and with an EDSS score <4 at baseline were the most adherent. The status of 'treatment adherent' in the first 3 months was predictive of higher adherence in the long term.

Keywords: Disease-modifying drugs; interferon beta; patient adherence; real-life setting; rebismart® injection device; relapsing-remitting multiple sclerosis.

MeSH terms

  • Adult
  • Female
  • Humans
  • Interferon beta-1a / administration & dosage*
  • Male
  • Middle Aged
  • Multiple Sclerosis, Relapsing-Remitting / drug therapy*
  • Patient Compliance*
  • Retrospective Studies


  • Interferon beta-1a