Prevalence of potentially inappropriate medicine use in older New Zealanders: a population-level study using the updated 2012 Beers criteria

Abstract

Rational, aims and objectives: To examine the prevalence of potentially inappropriate medicines (PIMs) in older New Zealanders at a population level.

Methods: De-identified prescription data for all individuals ≥65 years were obtained from the Pharmaceutical Claims Data Mart for 2011. International Classification of Diseases-10-AM (version 6) codes were used to extract diagnostic information from the National Minimum Datasets and PIMs were identified using the updated Beers 2012 criteria.

Results: 40.9% of older people were prescribed PIMs with approximately half dispensed ≥2 PIMs in 2011. Exposure was highest in individuals aged 65-74 years (68.9 ± 2.9). The most prevalent PIMs dispensed were diclofenac (6.0%), amitriptyline (4.9%), ibuprofen (4.6%), zopiclone (3.2%) and naproxen (3.0%). 66.3% of individuals were dispensed ≥1 and 80.8% were dispensed ≥2 medicines with a potential for drug-disease/syndrome interaction.

Conclusions: The updated Beers 2012 criteria identified that the use of PIMs at a population level is common in older New Zealanders.

Keywords: Beers criteria; aged; high-risk medicines; older people; potentially inappropriate medicines.