Old age, high risk medication, polypharmacy: a 'trilogy' of risks in older patients with atrial fibrillation.

BACKGROUND: The safety of pharmacotherapy in atrial fibrillation (AF) is compounded by a trilogy of risks old age, high-risk medications (e.g., antithrombotics, antiarrhythmics), polypharmacy due to multiple patient comorbidities. However, to date, scarce study has investigated the use of polypharmacy (including potentially inappropriate medication (PIM)) in AF patients, and how this may contribute to their overall risk of medication misadventure.

OBJECTIVES: To review the extent of polypharmacy and PIM use in older patients (65 years or older) with AF.

METHODS: Information was extracted from a database characterising a cohort of older AF patients treated in general practice in New South Wales, Australia. Patient characteristics, number and types of drugs, the degree of PIM use were recorded. The predictors for the use of polypharmacy in older AF patients were identified.

RESULTS: Overall, 367 patients (mean age 77.8 years) were reviewed, among which 94.8% used 5 medications or more and over half used 10 medications or more. Cardiovascular agents were most commonly used (98.9%), followed by antithrombotics (90.7%). Among agents deemed PIMs, digoxin (30.2%) was the most frequently used, followed by benzodiazepines (19.6%), and sotalol (9.8%). AF patients using polypharmacy were more likely to have low bleeding risk (OR=10.97), representing those patients in whom high-risk antithrombotics are mostly indicated. Patients with major-polypharmacy (5-9 medications) are more likely to have obstructive pulmonary diseases (OR=2.32), upper gastrointestinal diseases (OR=2.02) and poor physical function (OR=1.04), but less likely to have cognitive impairment (OR=0.27).

CONCLUSION: Polypharmacy affects oldest AF patients, comprising medications that are indicated for AF, yet regarded as PIMs. Patients with lower risk of bleeding, obstructive pulmonary diseases, upper gastrointestinal diseases and poor physical function are also at higher risk of using higher number of medications. This may lead to an increased risk for medication misadventure due to the concomitant use of polypharmacy and medications for AF.