# Overactive bladder medications and risk of emergency hospital admissions with delirium in adults without dementia: self-controlled case series

## TL;DR

Anticholinergic medications for overactive bladder increase delirium-related hospital admissions in older adults, especially men, but not mirabegron.

## Contribution

Identifies gender-specific and age-related delirium risks linked to anticholinergic OAB drugs using a self-controlled case series.

## Key findings

- Anticholinergic OAB medications increased delirium admission risk in the first 30 days for both men and women.
- Delirium risk remained elevated for men up to 365 days, but decreased over time for women.
- Mirabegron, a non-anticholinergic OAB drug, showed no significant delirium risk increase.

## Abstract

We examined whether anticholinergic overactive bladder (OAB) medications are associated with emergency hospital admissions with delirium in adults without dementia.

England’s primary care linked to inpatient records.

The source population comprised 215 293 adults initiating anticholinergic OAB medications (e.g. oxybutynin, solifenacin and tolterodine) during July 2010–December 2019 when aged ≥50 years, without dementia, severe mental illness or <12 months registration. We conducted self-controlled case-series including 1831 men and 1954 women with emergency hospital admissions with delirium. Incidence rate ratios (IRR) were estimated in risk periods during 6 months before and 12 months after initiating OAB medications, adjusted for time-varying age, separately in men and women.

The risk of delirium admissions was elevated for the first 1–30 days of prescriptions [IRR 1.54 (95% CI 1.30–1.82) for men, 1.44 (1.22–1.70) for women] and whilst reducing over time for women [1.10 (0.94–1.29) for 91–365 days of prescriptions], it remained elevated for men [1.38 (1.17–1.64)]. There was some evidence of greater delirium IRRs in older men and men initiating higher dosages. In secondary analysis of 502 adults initiating mirabegron (non-anticholinergic beta-3 receptor agonist), the delirium IRRs during the first 1–30 and 31–90 days of prescriptions were 1.15 (0.76–1.75) and 0.72 (0.47–1.09).

We observed increased hospital admission rates with delirium for adults without dementia whilst prescribed OAB anticholinergics, but not whilst prescribed mirabegron. Delirium risk remained raised for longer for men and was greater in older men. Alternative management options for OAB in older people should be considered before prescribing anticholinergic medications.