Preplanned Studies: Polypharmacy Among People Living with Dementia — Israel and 24 Countries in European Union, 2015–2019

From 2015–2019, the percentage of PLWD having polypharmacy varied substantially among Israel and 24 European Union countries, with approximately 1 in 5 Estonian PLWD and 4 in 5 Cypriot PLWD having polypharmacy. In addition, this percentage showed significantly higher trends in 4/25 of the countries studied. The findings of this study call attention to the endangering impact of polypharmacy (e.g., frailty, and impaired cognition). They also reinforce the importance of efforts to control polypharmacy among PLWD, especially in countries with increasing trends. The high percentage and the increasing trend of polypharmacy we identified are consistent with previous studies. A cross-sectional study of older adults in Denmark indicated that 62.6% of PLWD had polypharmacy in 2014 (8). While, a prospective cohort study of women with dementia in Australia showed that the prevalence of polypharmacy increased from 57.7% in 2003 to 71.2% in 2014 (5). The increasing comorbidity and long-term treatments may contribute to the rising prevalence of polypharmacy among PLWD (6). Compared to people without dementia, adverse health outcomes of polypharmacy may be worse for PLWD. Typical dementia symptoms such as memory loss and language problems may prevent the early detection of adverse drug events, leading to more severe complications and subsequent hospitalizations (2). Therefore, it is essential to deprescribe inappropriate medications among PLWD with polypharmacy. Medication review (e.g., the implementation of a routine medication management review system in Australia) and increasing the awareness of potentially inappropriate medicine use in the older population (e.g., the introduction of the red-yellow-green list, a list of potentially inappropriate medications tailored toward use, in Denmark) could be helpful to slow or even reverse such increasing trends (5-6).

The percentage and the time trend of polypharmacy varied substantially among studied countries. The disparities in the health system (e.g., whether the health system covers medicines for dementia and other chronic conditions) could influence the number of medications patients take. For instance, the relatively lower percentage of polypharmacy in Estonia is consistent with a study conducted in the UK, which estimated 22.3% of polypharmacy in 2010 (9). However, we cannot exclude the possibility of underutilizing corresponding services among the Estonian elderly, as revealed by a previous study (10). Future studies are needed to explore the possible reasons for the substantial cross-country variation identified in our report by further considering the differences in the health systems, differences like the availability, accessibility, and affordability of related resources. A study conducted in Denmark also found an inconsistency in the time trend of polypharmacy. It indicated that after the initiative of increasing the awareness of potentially inappropriate medicine use in 2011, no significant time trend of polypharmacy was found between 2011 and 2014, compared to an increasing trend between 2000 and 2010 (6). Future studies involving the interventions (e.g., policy evaluations and scoping reviews) on polypharmacy are also needed.

This report possesses the following strengths. First, this is the first multi-country study to investigate the polypharmacy trajectory among PLWD, enriching our limited understanding of this global health challenge. Second, the measurement of polypharmacy was consistent among countries, which enhanced the reliability of the variations identified in this report.

However, this report is subject to at least three limitations. First, polypharmacy may not be problematic if medications are reasonably prescribed. The distinction between appropriate and problematic polypharmacy is critical for PLWD who may be taking anti-dementia medications, because other medications may play a necessary role in reducing the progression or suppressing the symptoms of dementia. Future studies are recommended to evaluate problematic polypharmacy due to pharmacological inappropriateness such as drug-drug interactions. Second, SHARE has no information on the types of medications (e.g., anti-dementia or antidepressants), which prevented us from exploring the trends in the composition of polypharmacy. Third, some countries’ studies have apparent trends when only looking at point estimations in Figure 2, but no such significant odd ratios due to wide confidence intervals. These could be due to the potentially insufficient observations when studying dementia patients in each SHARE-covered nation. For instance, Luxembourg looks to be increasing but only had 98 participants in total. Although our primary findings on the high percentage and the increasing trend of polypharmacy we identified are consistent with previous studies as discussed above. Country-specific studies with more observations are needed.

In summary, future public health efforts must pay special attention to polypharmacy among PLWD. In countries with a higher prevalence of polypharmacy, healthcare providers should be aware of it when interacting with PLWD. They should also inform patients and their caregivers of the adverse effects of concurrent medications. Among countries with an increasing trend of polypharmacy, interventions and policies that promote medication review and awareness of potentially inappropriate medicine use should be considered.

The teams of Survey of Health, Ageing and Retirement in Europe (SHARE) for their efforts in data collection and for making the data publicly available; and Anqi Xu (School of Modern Languages and Cultures, University of Nottingham) for her valuable help in language polish.

No conflicts of interest.