Potentially inappropriate medication: prevalence, risk of hospitalisation and associated healthcare costs in the general older population of Switzerland

BACKGROUND: Potentially inappropriate medications (PIM) and their public health burden in the general older population in Switzerland remain largely unexplored. The aim of this study was to estimate the PIM prevalence and the association between the exposure to PIMs and the time to hospitalisation after PIMs as well as the total healthcare costs in the general older population of Switzerland. METHODS: We performed an observational retrospective study using health insurance claims data from patients aged 65 years or older. PIMs were defined based on the Beers criteria and the PRISCUS list. A repeated cross-sectional design was used to assess PIM prevalence, defined as the proportion of patients with PIM prescription. In a separate matched case-control design, a time-dependent multiple Cox proportional hazards regression was applied to examine the association between PIM prescription and time to first hospitalisation. To examine the association between the exposure to PIM and healthcare costs, a negative binomial regression model was used. RESULTS: In 2022, one-third of the population aged 65 years or older was prescribed at least one PIM. The highest risk of hospitalisation occurred within the first 15 days after the initial PIM prescription (hazard ratio [HR]: 2.72, 95% confidence interval [2.25–3.27]) and gradually decreased over time (after 30 days: HR: 2.16 [1.75–2.66]. 60 days: HR: 1.76 [1.50–2.05]. 90 days: HR: 1.67 [1.42–2.97]. 180 days: HR: 1.50 [1.37–1.66]. 365 days: HR: 1.34 [1.25–1.44]). Patients with PIM prescription showed on average CHF 3194 [3047.67–3341.10] higher costs than patients without PIM. CONCLUSION: This study showed a high PIM prevalence and associated public health burden in terms of hospitalisations and healthcare costs in the general older population of Switzerland. Our findings may indicate limited awareness in prescribing PIMs in primary care and the challenge associated with managing conflicting therapeutic recommendations in vulnerable patients. Given the ageing population and rising healthcare costs, the study highlights the urgent need for targeted strategies to reduce PIMs.