Associations of Potentially Inappropriate Medicine Use with Fall-Related Hospitalisations and Primary Care Visits in Older New Zealanders: A Population-Level Study Using the Updated 2012 Beers Criteria

BACKGROUND: Identifying potentially inappropriate medicines (PIMs) leading to adverse drug events may reduce the risk of morbidity and mortality in older people. OBJECTIVE: The aim of this study was to examine the relationship between exposure to PIMs and risk of Fall-related hospitalisations (FRH) and frequency of primary care visits in older New Zealanders. METHODS: Pharmaceutical collections (2011), diagnostic (2007–2011) and events (2012) information derived from the National Minimum Datasets were used to extract demographics, medication and diagnostic information for 537,387 individuals aged ≥65 years. Prescription and diagnostic information were matched through unique National Health Index numbers. The updated Beers 2012 criteria were used to identify PIMs. Polypharmacy was defined as five or more medicines dispensed concurrently for ≥90 days. RESULTS: Individuals exposed to one or more PIMs had an increased risk of FRH with an incidence rate ratio (IRR) of 1.45 (95 % confidence interval [CI] 1.37–1.52) and a greater number of primary care visits (IRR 1.15; 95 % CI 1.15–1.16). Individuals exposed to polypharmacy had an IRR of 1.41 (95 % CI 1.33–1.50) for FRH and an IRR of 1.14 (95 % CI 1.13–1.15) for primary care visits. CONCLUSION: PIMs identified by the 2012 Beers criteria showed an increased risk of FRH and a greater number of primary care visits. Age ≥85 years and female sex were identified as significant predictors of FRH and primary care visits.