Refill adherence and self-reported adverse drug reactions and sub-therapeutic effects: a population-based study

• Published in: Pharmacoepidemiology and drug safety 2013-12, Vol.22 (12), p.1317-1325
• Main Authors: Hedna, Khedidja, Hägg, Staffan, Andersson Sundell, Karolina, Petzold, Max, Hakkarainen, Katja M.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; adverse drug reaction; Adverse Drug Reaction Reporting Systems - statistics & numerical data; Aged; Aged, 80 and over; Biological and medical sciences; Clinical trial. Drug monitoring; Databases, Pharmaceutical; Drug Compounding - statistics & numerical data; Drug Utilization Review; Drug-Related Side Effects and Adverse Reactions - epidemiology; Farmakologi och toxikologi; Female; Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi; General pharmacology; Humans; Male; Medical sciences; Medication Adherence - statistics & numerical data; Middle Aged; oversupply; Pharmaceutical Preparations - supply & distribution; pharmacoepidemiology; Pharmacology; Pharmacology and Toxicology; Pharmacology. Drug treatments; Public Health, Global Health, Social Medicine and Epidemiology; refill adherence; Samhällsfarmaci och klinisk farmaci; self-report; Side effects; Social and Clinical Pharmacy; Sweden - epidemiology; therapeutic failure; undersupply; Young Adult
• ISSN: 1053-8569; 1099-1557; 1099-1557
• DOI: 10.1002/pds.3528

ABSTRACT Purpose 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. Method 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. Conclusions 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. Copyright © 2013 John Wiley & Sons, Ltd.