Determinants of non-adherence to disease-modifying therapies in multiple sclerosis: A cross-Canada prospective study

Mult Scler. 2017 Apr;23(4):588-596. doi: 10.1177/1352458516657440. Epub 2016 Jul 11.

Abstract

Background: Poor adherence to the disease-modifying therapies (DMTs) for multiple sclerosis (MS) may attenuate clinical benefit. A better understanding of characteristics associated with non-adherence could improve outcomes.

Objective: To evaluate characteristics associated with non-adherence to injectable DMTs.

Methods: Consecutive patients from four Canadian MS Clinics were assessed at three time points over two years. Clinical and demographic information included self-reported DMT use, missed doses in the previous 30 days, health behaviors, and comorbidities. Non-adherence was defined as <80% of expected doses taken. We employed generalized estimating equations to examine characteristics associated with non-adherence at all time points with findings reported as adjusted odds ratios (OR).

Results: In all, 485 participants reported use of an injectable DMT, of whom 107 (22.1%) were non-adherent over the study period. Non-adherence was associated with a lower Expanded Disability Status Scale score (0-2.5 vs 3.0-5.5, OR: 1.80; 95% confidence interval (CI): 1.06-3.04), disease duration (⩽5 vs <5 years, OR: 2.23; 95% CI: 1.10-4.52), alcohol dependence (OR: 2.14; 95% CI: 1.23-3.75), and self-reported cognitive difficulties, measured by the Health Utilities Index-3 (OR: 1.55; 95% CI: 1.08-2.22).

Conclusions: Nearly one-quarter of participants were non-adherent during the study. Alcohol dependence, perceived cognitive difficulties, longer disease duration, and mild disability status were associated with non-adherence. These characteristics may help healthcare professionals identify patients at greatest risk of poor adherence.

Keywords: Multiple sclerosis; adherence; beta-interferon; glatiramer acetate; health behavior; immunomodulatory therapy.

MeSH terms

  • Adult
  • Aged
  • Canada
  • Female
  • Glatiramer Acetate / therapeutic use*
  • Humans
  • Immunosuppressive Agents / therapeutic use*
  • Interferon-beta / therapeutic use*
  • Male
  • Medication Adherence / statistics & numerical data*
  • Middle Aged
  • Multiple Sclerosis / drug therapy*
  • Prospective Studies
  • Risk
  • Treatment Outcome
  • Young Adult

Substances

  • Immunosuppressive Agents
  • Glatiramer Acetate
  • Interferon-beta