Background: Polypharmacy and hyperpolypharmacy are proxy indicators for inappropriate medicine use. Inappropriate medicine use in older people leads to adverse clinical outcomes. Objective: The objectives of this study were to investigate the prevalence and trends of polypharmacy and hyperpolypharmacy in older people in New Zealand from 2005 to 2013, analyzing the pharmaceutical collections maintained by the Ministry of Health. Methods: A repeated cross-sectional analysis of population-level dispensing data was conducted from January 1, 2005 to December 31, 2013. Polypharmacy and hyperpolypharmacy in individuals were defined as the use of 5-9 medicines and ≥10 medicines, respectively, dispensed concurrently for a period of ≥90 days. Differences in polypharmacy and hyperpolypharmacy between 2005 and 2013 were examined. A multinomial regression model was used to predict sociodemographic characteristics associated with polypharmacy and hyperpolypharmacy. Results: Polypharmacy and hyperpolypharmacy were found to be higher in 2013 compared to 2005 (polypharmacy: 29.5 vs. 23.4%, p < 0.001; hyperpolypharmacy: 2.1 vs. 1.3%, p < 0.001). The risk of polypharmacy and hyperpolypharmacy was higher in females, in those aged 80-84 years, in the Māori population (for polypharmacy) and the Middle Eastern, Latin American, or African population (for hyperpolypharmacy), in people living in the Southern-district health board, and in individuals with increasing deprivation. Conclusion: The population of New Zealand is aging and the number of older people with multiple chronic conditions is increasing. The proportion of older people exposed to polypharmacy and hyperpolypharmacy has increased in 2013 compared to 2005. Our study provides important information to alert health policy makers, researchers, and clinicians about the dire need to reduce the medication burden in older New Zealanders.

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