Mirabegron (MI) is the first β3-adrenoceptor agonist to enter clinical practice, and has been approved for the treatment of symptoms of overactive bladder (OAB) in many countries. Recent study proved that combination therapy with MI and an antimuscarinic agent such as solifenacin may provide an attractive therapeutic option to maximize efficacy and minimize the burden of adverse event (AE)s[1]. Furthermore, adherence rate of MI in Canada[2], and UK[3] have been reported as about 40%. In Japan, we have more than 5 years’ experience of prescription of MI. The aims of this study were to analyse the adherence rate of MI in Japanese patients with OAB, to compare the persistence rate between male and female, and to compare single and combined pharmacotherapies.

Between September 2011 and December 2016, 1211 Japanese patients with OAB were treated with MI in a private Urology out-patient clinic in Yamanashi Prefecture, Japan. Retrospective chart review was performed including several parameters (IPSS, OABSS [Urology, 68:318, 2006.]). Data were analysed using Student’s t-tests, or Kaplan-Meier estimate and Cox-Mantel test. This study has been approved by the Ethical Committee, University of Yamanashi. School of Medicine. Informed consents were obtained from the all participants.

1)	Age: Among 1211 patients with OAB, 70% (843) and 30% (368) were male and female, respectively. Average age were 73.7, 73.3, and 74.8 years old in total, male and female patients, respectively. Eighty-two % (989) were over 65 years old, and 18% (222) were under 65 years of age. Among age group of decades, 70 to 80 years were highest incidence in total, male and female patients, followed by 80 to 90 years old, then 60 to 70 years old.
2)	Types of pharmacotherapies: Solo-administration of MI were 41% (346), 
and 60% (222) in male and female patients groups, respectively. Patients administered with combination of MI and alpha1-blocker were 45% (377) in male group, and patients administered with combination of MI and anti-cholinergic were 40% (146) in female group.
3)	Persistence rate of MI: Overall rate of persistence of MI were 37.6%, 29.9%, 25.6%, 22.2%, and 19.4%, at 12months, 24months, 36months, 48months, and 60months, respectively. Rate of persistence of MI in male were 39.3%, 30.4%, 26.1%, 22.9% and 16.9%, at 12months, 24months, 36months, 48months, and 60months, respectively. Rate of persistence of MI in female were 33.7%, 28.9%, 24.7%, 20.8% and 19.2%, at 12months, 24months, 36months, 48months, and 60months, respectively.
4)	Persistence rate and types of pharmacotherapies (single and combinations): Persistence rate of MI-single were 17.1%, 12.6%, 9.8%, 8.4%, and 8.4% at 12months, 24months, 36months, 48months, and 60months, respectively. Persistence rate of MI with alpha-1 blocker in male patients were 46.6%, 36.4%, 32.8%, 28.7%, and 21.1% at 12months, 24months, 36months, 48months, and 60months, respectively. Persistence rate of MI with anti-cholinergic in female patients were 65.7%, 55.5%, 48.3%, 42.0%, and 37.9% at 12months, 24months, 36months, 48months, and 60months, respectively. Persistence rate of MI with alpha-1 blocker and anti-cholinergic were 70.9%, 62.3%, and 56.7% at 12months, 24months, and 36months, respectively. There are significant difference (p<0.001) between any combinations except for MI-single and MI with alpha-1 blocker (Figure 1).

Although more than 1,200 patients were included in this syudy, 70% were male. Usually, OAB pharmacotherapy data were obtained mainly from female population, however, most of BPH/Male LUTS patients complains not only voiding symptoms, but storage symptoms including OAB. Persistence rate of MI-single were not high (8.4% at 60months), however, persistence rate of MI with alpha-1 blocker in male patients were 32.8% and 21.1% at 36months and 60months, respectively, and persistence rate of MI with anti-cholinergic in female patients were 48.7% and 37.9%, and at 36months and 60months, respectively. Furthermore, persistence rate of MI with alpha-1 blocker and anti-cholinergic were 56.7% at 36months, far higher than any combinations (p<0.001) in male patients. One explanation of those results was that patients with severe symptoms require double or triple combination therapies.

MI has been well accepted and tolerated as a therapy for male and female OAB patients in Japan. Combination of MI and anti-cholinergic might be an effective and safe treatment for female patients, and triple combination of MI, alpha1-blocker, and anti-cholinergic might be a good option for male OAB patients.

Yamaguchi, O., Kakizaki, H., Homma, Y., et al.: Safety and efficacy of
Wagg, A, Franks, B, Ramos, B, et al.:Persistence and adherence with
Chapple CR, Nazir J, Hakimi Z, et al.,Persistence and Adherence with