Background: Polypharmacy in older people is steadily increasing and a combination of many medicines may result in adverse effects, especially if the medicines interact pharmacodynamically. Examples are additive or synergistic effects increasing the risk of falls, haemorrhage, serotonin syndrome and torsade de pointes. The clinical decision support system Janusmed Risk Profile has been developed to find such risks based on a patients' medication list.
Objectives: The main aim of this retrospective register-based study was to study what pharmacodynamic risks older patients (aged 65 years or older) on polypharmacy (defined as using five or more medicines) are exposed to. Second, we studied if the introduction of the Janusmed Risk Profile in the main electronic health record system in Region Stockholm influenced the proportion of patients prescribed combinations that increase the risk for the nine adverse-effect categories defined (anticholinergic effects, haemorrhage, constipation, orthostatism, QT prolongation, renal toxicity, sedation, seizures and serotonin syndrome).
Methods: Data on all prescription medicines to individuals aged 65 years or older, and with at least five concomitant medicines were retrieved and analysed for the risk categories in the Janusmed Risk Profile. The proportions of patients with a high/moderate risk during a 4-month period before (period 1) and after (period 2) the introduction were compared.
Results: A total of 127,719 patients in period 1 (November 2016-February 2017), and 131,458 patients in period 2 (November 2017-February 2018) were included in the study. The proportion of patients with a high or moderate risk for each of the nine properties (anticholinergic effects, haemorrhage, constipation, orthostatism, QT prolongation, renal toxicity, sedation, seizures and serotonergic effects) were 10.9, 34.7, 32.8, 33.6, 17.2, 0.7, 15.4, 0.5 and 2.4%, respectively, in period 1 and 10.4, 35.5, 32.8, 33.3, 10.8, 0.71, 14.9, 0.5 and 2.3% in period 2. The changes for sedation and QT prolongation were statistically significant, with the most pronounced decrease for QT prolongation from 17.2 to 10.8% (p < 0.001). When analysing patients at a high risk, the decrease was significant for haemorrhage, orthostatism, QT prolongation and sedation.
Conclusions: Older people are exposed to combinations of medications that increase the risk for potentially severe adverse effects. Prescribers seem to respond especially to warnings for QT prolongation, presented in the Janusmed Risk Profile implemented in the electronic health record system.
© 2023. The Author(s).