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Abstract
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AIM: To explore longitudinal changes in the number and type of medicines used among older people who experience polypharmacy.
METHODS: We used pharmaceutical claims for a 10% sample of Australian Pharmaceutical Benefits Scheme beneficiaries to identify people aged 70 years and over who were exposed to five or more medicines on February 15, 2014. Using group-based trajectory modelling, we explored changes in the quarterly number and type of medicines used over a five-year period (2014-2018).
RESULTS: In our cohort of 98,539 people, we identified two predominant groups of medicine use: sustained polypharmacy (77% of people, 4 trajectories); and decreasing medicine use (23%, 3 trajectories). Within the sustained polypharmacy group, people in trajectories with a lower mean number of medicines (e.g. 6 unique medicines) had relatively stable trajectories, while those using a higher number of medicines (e.g. 15 unique medicines) experienced greater seasonal variation in the number and type of medicines used. On average, people continued to use two-thirds of their medicines (chemical substance level) across adjacent quarters. Within groups of decreasing medicine use, the most common trajectory was a slight drop in medicines within three months. Overall, 79% of people still experienced polypharmacy after one year.
CONCLUSION: Polypharmacy among older people is a sustained phenomenon, reflecting the
chronic nature of multimorbidity within this population. However, there is an underlying volatility in the nature of medicines involved, reflecting both changes in treatment and seasonal fluctuation in dispensing. Ongoing prescribing vigilance is required, particularly for patients using very large volumes of medicines.
Language: en |