Division of Drug Research, Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University, County Council of Östergötland, Sweden; Nordic School of Public Health NHV, Gothenburg, Sweden.
Pharmacoepidemiol Drug Saf. 2013 Dec;22(12):1317-25
To assess refill adherence to dispensed oral long-term medications among the adult population and to investigate whether the percentages of self-reported adverse drug reactions (ADRs) and sub-therapeutic effects (STEs) differed for medications with adequate refill adherence, oversupply, and undersupply.
Survey responses on self-reported ADRs and STEs were linked to the Swedish Prescribed Drug Register in a cross-sectional population-based study. Refill adherence to antihypertensive, lipid-lowering, and oral anti-diabetic medications was measured using the continuous measure of medication acquisition (CMA). The percentages of self-reported ADRs and STEs were compared between medications with adequate refill adherence (CMA 0.8-1.2), oversupply (CMA?>?1.2), and undersupply (CMA??0.5) for ADRs and 1.1%, 1.6%, and 1.5% (p?>?0.5) for STEs.
Adequate refill adherence was found in two thirds of the medication therapies. ADRs and STEs were unexpectedly equally commonly reported for medications with adequate refill adherence, oversupply, and undersupply. These results suggest that a better understanding of patients' refill behaviors and their perceived medication adverse outcomes is needed and should be considered in improving medication management. The impact of individual and healthcare factors that may influence the association between refill adherence and reported medication adverse outcomes should be investigated in future studies.