ObjectivesTo assess the effect of 25 or 50 mg mirabegron on cardiovascular end-points and adverse drug reactions in real-world Japanese patients with overactive bladder and cardiovascular disease. MethodsParticipants had overactive bladder, a history of/coexisting cardiovascular disease and a 12-lead electrocardiogram carried out 7 days before initiating 4 weeks of mirabegron treatment. Patients with serious cardiovascular disease (class III or IV on the New York Heart Association functional classification and further confirmed by expert analysis) were excluded. Patient demographics, physical characteristics and cardiovascular history were recorded. After 4 weeks, patients underwent another electrocardiogram. Incidence of cardiovascular adverse drug reactions and change from baseline in electrocardiogram parameters (RR, PR, QRS intervals, Fridericia's corrected QT and heart rate) were assessed. ResultsOf 316 patients registered, 236 met criteria and had baseline/post-dose electrocardiograms: 61.9% male; 60.2% aged 75 years; 93.6% with coexisting cardiovascular disease, notably, arrhythmia (67.8%) and angina pectoris (19.1%). Starting mirabegron daily doses were 25 mg (19.9%) or 50 mg (80.1%). The incidence of cardiovascular adverse drug reactions was 5.51%. After 4 weeks, the mean heart rate increased by 1.24 b.p.m. (statistically significant, but clinically acceptable as per previous trials). No significant changes were observed in PR, QRS or Fridericia's corrected QT. No significant correlations in the total population or age-/sex-segregated subgroups were observed between baseline Fridericia's corrected QT and change at 4 weeks. No correlation for heart rate versus change from baseline heart rate with treatment was observed. ConclusionsMirabegron was well tolerated in real-world Japanese patients with overactive bladder and coexisting cardiovascular disease. No unexpected cardiovascular safety concerns were observed.