[Epidemiology of polypharmacy in primary healthcare in the Reykjavik metropolitan area 2010-2019]

Taking medicines can induce risks leading to negative health issues that can grow in accordance with the number of medicines used. Many studies on the prevalence of polypharmacy have been carried out in other countries, but such studies are lacking in Iceland. The aim of this study was to analyse the prevalence of polypharmacy in primary care in the Reykjavik metropolitan area.

The study population consisted of individuals who had been prescribed five or more drugs by physicians in primary care in the Reykjavik metropolitan area during the study period. Data was collected on all drug prescriptions for individuals in the area. Those who had five or more drugs prescribed in the primary healthcare database from 1 January 2010 through 31 December 2019 were included in the study. According to Statistics Iceland, the total number of inhabitants in the area was 200.907 in 2010 and 228.222 in 2019.

The prevalence of polypharmacy increased gradually in 2010-2019, or by 37.9% during this period. Patients with polypharmacy were 9.8% (19.778) at the beginning of the study in 2010 and increased to 13.6% (30.970) in 2019. A clear association was observed between age and polypharmacy, and the study showed polypharmacy to be more common among women. The study findings revealed that the greatest relative increase in polypharmacy was among young people from 20-49 years of age. ATC class analysis showed a sharp increase in the first and third levels of the ATC subgroups.

The findings suggest polypharmacy to be common in the Reykjavik metropolitan area. Similarly, its prevalence seems to be increasing in younger patients. It is important to gain a better understanding of the reasons for the development of polypharmacy and evaluate the increasing medicalisation in society. The underlying reasons, as well as the effects of polypharmacy, can lead to both positive and negative health outcomes.