Purpose: To describe and compare self-reported medication adherence assessed with the 5-item version of Medication Adherence Report Scale (MARS-5) and pharmacy refill adherence based on data from the Swedish Prescribed Drug Register (SPDR) among persons with ischemic stroke, and to investigate independent predictors associated with respective assessments.
Methods: A study questionnaire was sent to persons with ischemic stroke registered in the Swedish Stroke Register between Dec 2011 and March 2012, and who lived at home 3 months after discharge. The primary outcome was dichotomized to adherent/non-adherent based on MARS-5 and SPDR and analyzed with multivariable logistic regression. Adherence according to MARS-5 was defined as score 23 or higher (out of 25). Adherence according to SPDR was defined as at least one filled statin prescription recorded in SPDR in each 6-month interval during 2 years of follow-up.
Results: Of 420 participants, 367 (87%) and 329 (78%) were adherent according to MARS-5 and SPDR, respectively, and 294 (70%) participants were adherent according to both assessments. A significant association was shown between medication adherence according to the two assessments (p = 0.020). Independent predictors associated with medication adherence according to MARS-5 were female sex, while factors associated with SPDR were male sex and being younger.
Conclusions: The majority of participants were classified as adherent, 87% according to MARS-5 and 78% based on data from SPDR. However, only 70% were adherent according to both MARS-5 and SPDR, and different predictors were associated with the different measurements, suggesting that these assessments are measuring different aspects of adherence.