Geographic Variation in Top-10 Prescribed Medicines and Potentially Inappropriate Medication in Portugal: An Ecological Study of 2.2 Million Older Adults

Multiple medication intake by older adults is considered a serious public health concern since it is associated with increased risk of adverse drug reactions and potentially inappropriate medication (PIM). This study described the top-10 prescribed active substances considering geographical distribution and PIM prescription in older adults. A cross-sectional ecological study using data on the active substances prescribed to people aged 65 years or older during 2020 was conducted. Information on active substances and the respective defined daily doses (DDD) stratified by age group, sex and region were collected from a Portuguese health administrative database. The average number of prescribed packages and DDD per 1000 inhabitants per day of top-10 active substances were assessed. This study included a total of 2,228,090 older adults (58% females). The furosemide and atorvastatin were the active substances with higher prescription rates (mean DDD/1000 inhabitants/day) in all ARS in both males and females, in comparison with the other top-10 active substances. Our results showed geographic differences in prescription, illustrated by more prescriptions in ARS North and Centre and fewer prescriptions in ARS Algarve. In females, two out of the 10 most prescribed active substances were PIM (benzodiazepines and opioids). Geographic disparities in PIM prescription across Portuguese regions were also observed. This study shows that drugs for the cardiovascular system were the active substances most prescribed to older adults. The prescription of benzodiazepines and opioids, classified as PIM, among females, alerts officials to the need of health policies to decrease inappropriate medication. The observed geographic differences in the 10 most prescribed active substances and in PIM prescription emphasized the importance of investing in medication optimization across the Portuguese regions.