Association Between Cholinesterase Inhibitor‐Overactive Bladder Antimuscarinic Prescribing Cascade and Risk of Delirium and Falls Among Individuals Living With Dementia

ABSTRACT Background Prescribing cascades occur when cholinesterase inhibitor (ChEI)‐induced urinary incontinence is misinterpreted as a new condition, leading to overactive bladder (OAB) antimuscarinic initiation. We evaluated whether the ChEI‐OAB antimuscarinic prescribing cascade was associated with delirium or falls compared with mirabegron in older adults living with dementia. Methods We conducted a retrospective cohort study using the Anlitiks All‐Payor Claims database (2015–2020). Participants were adults aged ≥ 65 years with dementia newly prescribed a ChEI with no prior ChEI or OAB therapy (180 days). A 60‐day window identified OAB treatment initiation after ChEI therapy. Exposures were OAB antimuscarinics or mirabegron. Outcomes were incident delirium and falls identified using diagnosis codes. Propensity score‐based weighting balanced baseline characteristics. Results Among 2693 patients (mean age 80 years; 66.3% female), 201 (7.5%) initiated antimuscarinics and 2492 (92.5%) started mirabegron. Over 1 year, 8 (4.0%) antimuscarinic users developed delirium versus 95 (3.8%) mirabegron users (adjusted HR 1.35; 95% CI, 0.64–2.86). Falls occurred in 3 (1.5%) antimuscarinic users and 63 (2.5%) mirabegron users (adjusted HR 0.66; 95% CI, 0.20–2.15). Conclusions In older adults living with dementia, the estimated association between initiation of OAB antimuscarinics following ChEIs and the risks of delirium or falls, compared with mirabegron, was statistically compatible with benefit, harm, or no clinically meaningful difference. These findings highlight the need to evaluate whether OAB antimuscarinics are prescribed in response to true clinical need or as part of a prescribing cascade. Given the limited number of outcome events and resulting wide 95% CIs, future studies are needed to more precisely estimate the risk.