Sex Differences in Prescribing Patterns of Anticholinergics and β3-Adrenoceptor Agonists for Overactive Bladder: A...

Drug treatment for overactive bladder (OAB) is changing, with an increasing share of β3-adrenoceptor agonists relative to anticholinergics, but it is not known how far this change has progressed in older people, who are most vulnerable to the risks of anticholinergics. We examined the use of these drugs in Japan by age and sex, and analyzed changes in anticholinergic burden using a large database.

We analyzed outpatient prescriptions of two β3-adrenoceptor agonists and six anticholinergics from FY2017 to FY2024, using the sex- and age-stratified tables of the NDB Open Data of Japan. Dispensed tablets were converted into patient-days, and the β3-adrenoceptor agonist share was calculated. Anticholinergic burden was measured as ACB-weighted prescription volume (patient-days multiplied by the anticholinergic cognitive burden score). Because FY2021-FY2022 was a period of nationwide generic supply disruption, FY2018 and FY2024 were used as endpoints when estimating change over time.

The β3-adrenoceptor agonist share rose from 36.2% to 64.9%, but anticholinergic use fell only slightly (3.10 × 10⁸ to 2.94 × 10⁸ tablets; -5.0%). In FY2024, the β3-adrenoceptor agonist share was higher in men than in women in every age group, and the difference widened with age (+1.2 percentage points at 50-54 years and +14.2 at ≥ 90 years). ACB-weighted prescription volume was higher in women than in men, and the female-to-male ratio rose with age (1.1 at 65-74 years, 1.6 at 75-84 years, and 2.8 at ≥ 85 years). Between FY2018 and FY2024, prescription volume fell by about 20% at 65-74 and 75-84 years, but the fall was smallest in women aged ≥ 85 years (-11.3%).

The β3-adrenoceptor agonist share for OAB has continued to increase in Japan, but this change appears slower in older women, in whom anticholinergic exposure remains high.