Risk of overactive bladder associated with cholinesterase inhibitors in dementia

BACKGROUND Although cholinesterase inhibitors (ChEIs) are the primary treatment for dementia, they are associated with overactive bladder (OAB), necessitating antimuscarinic use. Limited data exist regarding the risk of OAB across individual ChEIs in dementia. This study evaluated the risk of OAB associated with individual ChEIs in older adults with dementia. METHODS This was a new user retrospective cohort study using Medicare claims data involving Parts A, B, and D claims dataset from 2013 to 2015. The study included older adults (aged 65 and older) with a diagnosis of dementia using donepezil, galantamine, or rivastigmine. New ChEI claims were identified with a 6-month baseline washout period. Patients with OAB diagnosis or any antimuscarinic or mirabegron use in the baseline period were excluded. The primary outcome of interest was OAB diagnosis or prescription of antimuscarinics or mirabegron within 6 months of ChEI initiation. Multivariable cox proportional hazards regression with propensity scores (PS) as covariates and inverse probability of treatment weighting generated using generalized boosted models was used to assess the risk of OAB among donepezil, galantamine, and rivastigmine users. RESULTS The study included 524,975 older adults with dementia who were incident users of ChEIs (donepezil 80.72%, rivastigmine 16.41%, galantamine 2.87%). Overall, OAB diagnosis/antimuscarinic/mirabegron prescription was observed in 5.07% of the cohort within 6 months of ChEIs prescription. The Cox regression model with PS as covariate approach found that donepezil use increased the risk of OAB compared to rivastigmine (aHR, 1.13; 95% CI, 1.08-1.28; p < 0.0001). However, there was no differential risk of OAB between galantamine and rivastigmine. The findings were consistent with the generalized boosted models. CONCLUSIONS The study found that the risk of OAB varies across individual ChEIs with an increased risk of OAB with donepezil compared to rivastigmine. The study findings suggest the need to understand and manage medication-related morbidity in older adults with dementia.