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Overactive Bladder

Older Koreans on overactive bladder medication carried 15 times the anticholinergic burden, and two-thirds of it came from the bladder drug itself

A cumulative cognitive burden score of 320.1 against 21.0 over 100 days. Mirabegron contributed exactly none of it, which is the practical finding.

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In short

In a retrospective analysis of South Korean National Health Insurance Service data covering patients aged 65 or over with at least one outpatient visit between January and June 2016, comprising 2,360 patients with overactive bladder and 11,676 matched patients without it, the mean 100-day cumulative anticholinergic cognitive burden score was 15.2 times higher in the overactive bladder group (320.1 against 21.0), anticholinergics were used by 96.9 percent of overactive bladder patients against 33.6 percent of the others, strong anticholinergic use was almost four times more prevalent (94.7 against 24.1 percent), and the share of burden attributable to the bladder medication itself was 66.9 percent in the antimuscarinic-only group, 64.3 percent with antimuscarinic plus mirabegron, and zero in the mirabegron-only group.

Key takeaways

  • 2,360 Korean patients aged 65 or over with overactive bladder were compared with 11,676 matched patients without it, using National Health Insurance Service data.
  • The mean 100-day cumulative anticholinergic cognitive burden score was 320.1 in the overactive bladder group against 21.0 in the comparison group — 15.2 times higher.
  • Anticholinergic medication was dispensed to 96.9 percent of overactive bladder patients against 33.6 percent of those without it.
  • Strong anticholinergic use was almost four times more prevalent, at 94.7 against 24.1 percent.
  • Of the burden score, 66.9 percent was attributable to the bladder medication in the antimuscarinic-only group and 64.3 percent in the antimuscarinic-with-mirabegron group.
  • Mirabegron alone contributed zero anticholinergic burden.
  • The authors conclude that clinicians should weigh each patient's total anticholinergic burden when choosing overactive bladder pharmacotherapy.

Anticholinergic burden is a running total rather than a property of any single prescription. Drugs for allergy, depression, sleep, Parkinson's disease, incontinence and nausea all carry anticholinergic activity, and the concern in older patients — cognitive impairment and, on longer horizons, dementia — attaches to the sum rather than to any one entry in it. This study asked how much of that sum, in older Koreans, comes from the bladder.

320.1 vs 21.0

mean 100-day cumulative anticholinergic cognitive burden score, overactive bladder patients aged 65 and over against matched patients without itLee KS et al., International Neurourology Journal, 2025

The gap is not explained by being older or sicker

Patients were matched, and both groups were drawn from the same population of over-65s with an outpatient visit in the first half of 2016. A fifteen-fold difference does not come from the comparison group being healthier. It comes from what overactive bladder is treated with: 96.9 percent of this group received an anticholinergic, and 94.7 percent received one classed as strong.

The attribution analysis then closes the loop. In patients on antimuscarinics alone, 66.9 percent of their entire anticholinergic cognitive burden came from the bladder drug. Two-thirds of a burden associated with cognitive harm in older people, traced to a medication given for urinary urgency.

The alternative that scores zero

Mirabegron works through a different receptor — a beta-3 adrenergic agonist rather than a muscarinic antagonist — and it contributed zero to the burden score. Not a low figure. Zero, by mechanism. In the group taking an antimuscarinic together with mirabegron, the bladder-attributable share was 64.3 percent, which is barely different from antimuscarinic alone, because the antimuscarinic is still doing all of the damage.

What the claims data can see

Dispensing is not the same as swallowing, and an average of 0.9 anticholinergics per patient across the whole cohort means the burden is concentrated rather than universal. The 100-day window is also short: it captures a period of exposure well and says nothing about years of it, which is the timescale on which the cognitive concern actually operates.

Sources

  1. 1

    Lee KS, Cho J, Kang D, Ko KJ, Foo CY, Stoelzel M, Hadi FA, Kim S

    A Retrospective Database Analysis of Anticholinergic Burden Among Older Patients With and Without Overactive Bladder in South Korea

    International Neurourology Journal 2025;29(3):188-196

    doi:10.5213/inj.2550112.056 · PMID:41077792

    https://doi.org/10.5213/inj.2550112.056