Presentation Authors: Rano Matta*, Simon Greaves, David Juurlink, Muhammad Mamdani, Tara Gomes, Mina Tadrous, Toronto, Canada
Introduction: Mirabegron, a Î²-3 adrenoreceptor agonist, used to treat overactive bladder (OAB) has been shown in clinical trials to produce a minor increase in resting heart rate, blood pressure, and QTc interval. More patients are being prescribed mirabegron, owing to its limited adverse effects relative to antimuscarinic OAB drugs. However, there is a lack of cardiovascular safety data in older patients and those with existing cardiovascular disease. We evaluated the risk of cardiac arrhythmias and other adverse cardiovascular events in older patients using mirabegron relative to other OAB agents.
Methods: We conducted a population-based cohort study of patients â‰¥66 years old who were new users of OAB drugs between June 1, 2015 and March 31, 2017 in Ontario, Canada. We followed patients for one year after starting the medication or until they discontinued or switched treatment. The primary outcome was a composite of hospitilization or emergency room visit for arrhythmia and tachycardia events. The secondary outcome was myocardial infarction (MI) or stroke. Patients taking mirabegron were matched to subjects taking other OAB agents on age, sex, date of initiating medication, and a high dimensional propensity score. The primary analysis used Cox proportional hazards regression.
Results: We matched 16,948 mirabegron users to 21,870 users of other OAB drugs. The median age of the cohort was 76 (Interquartile range 71-83), and most were female (N=25,189, 64.9%). A large proportion of the cohort had hypertension (N=30,393, 78.3%) and diabetes (N=13,757, 35.4%). Overall, 624 (1.6%) patients experienced an arrythmia or tachycardia event and 480 (1.2%) experienced an MI or stroke. The 1-year cumulative incidence of arrhythmia or tachycardia events was 3.3% in the mirabegron group and 3.5% in the other OAB drugs group (adjusted? Hazard Ratio [HR] 0.93; 95% Confidence Interval [CI] 0.80-1.09). Mirabegron was not associated with an increased risk of MI or stroke compared to other OAB drugs (HR 1.06; 95% CI 0.89-1.27).
Conclusions: In a population-based cohort of older patients, use of mirabegron was not associated with an increased risk of arrhythmia or other cardiovascular events compared to other OAB drugs. These results are supportive of current prescribing trends and give a balanced view of real-world safety of this treatment option.