Use of bladder antimuscarinics is associated with an increased risk of dementia: a retrospective population-based case-control study

Risks of Dementia After Treatment with an Anticholinergic, Beta-3 Agonist, or Combination of Both for an Overactive Bladder: A Korean National Cohort Study

BACKGROUND AND OBJECTIVE

An overactive bladder (OAB) is primarily managed with behavioural therapy and using anticholinergics and beta-3 agonists. Reports have shown that the use of anticholinergics by OAB patients was associated with an increased risk of new-onset dementia compared with those using beta-3 agonists. This study compares the risks of dementia among patients with an OAB starting on a beta-3 agonist alone, an anticholinergic alone, or a combination treatment.

METHODS

Using data from the Korean National Health Insurance Service database, we studied a nationwide population cohort comprising patients newly diagnosed with an OAB who initiated their OAB medications between 2015 and 2020. The treatment types were categorised as anticholinergics (oxybutynin, solifenacin, tolterodine, trospium, fesoterodine, flavoxate, and propiverine) alone, a beta-3 agonist (mirabegron) alone, and combination therapy (an anticholinergic plus the beta-3 agonist). To evaluate the impact of cumulative drug exposure, we quantified the cumulative exposure to solifenacin and mirabegron as cumulative defined daily doses (cDDDs) using proportional hazards regression analyses, adjusted for factors known to be associated with dementia.

KEY FINDINGS AND LIMITATIONS

Among the study's 3 452 705 patients, 671 974 were new users of a beta-3 agonist alone (19.5%), 1 943 414 new users of anticholinergics alone (56.3%), and 837 317 receiving combination therapy (24.3%). The most common anticholinergic used both alone and as part of a combination treatment was solifenacin (42.9% and 56.3%, respectively). There was an increased risk of dementia between the users of an anticholinergic alone (adjusted hazard ratio [aHR] = 1.213; 95% confidence interval [CI], 1.195-1.232) and those taking a combination treatment (aHR = 1.345; 95% CI, 1.323-1.366) compared with the users of beta-3 agonists alone after the adjustment of covariates. However, the incidence of dementia was also significantly higher, with an increase in the cumulative dose of mirabegron (aHR = 1.062 [1.021-1.106] for 28-120 cDDDs and aHR = 1.044 [1.004-1.084)] for patients who received >121 cDDDs compared with those who received <27 cDDDs). A marked increased risk of dementia was associated with the use of solifenacin, tolterodine, fesoterodine, and propiverine, both separately and in combination with mirabegron.

CONCLUSIONS AND CLINICAL IMPLICATIONS

In this large Korean cohort, the use of anticholinergics with or without a beta-3 agonist increased the risk of new-onset dementia compared with the use of a beta-3 agonist alone. Given that the risk of dementia was most significantly elevated with combination treatments, care should be taken when considering combination treatment for OAB patients with risk factors for dementia. Furthermore, there could be a possible association between beta-3 agonists and dementia, although future studies are needed.

PATIENT SUMMARY

This study investigated the risk of dementia induced by overactive bladder (OAB) treatment in a large Korean cohort. Two representative OAB treatment drugs, anticholinergics and beta-3 agonists, both increased the risk of new-onset dementia. Clinicians should be cautious in using OAB treatment drugs since no drugs could be concluded as safe.

The Effectiveness in Activating M-Type K+ Current Produced by Solifenacin ([(3R)-1-azabicyclo[2.2.2]octan-3-yl] (1S)-1-phenyl-3,4-dihydro-1H-isoquinoline-2-carboxylate): Independent of Its Antimuscarinic Action

Solifenacin (Vesicare^®, SOL), known to be a member of isoquinolines, is a muscarinic antagonist that has anticholinergic effect, and it has been beneficial in treating urinary incontinence and neurogenic detrusor overactivity. However, the information regarding the effects of SOL on membrane ionic currents is largely uncertain, despite its clinically wide use in patients with those disorders. In this study, the whole-cell current recordings revealed that upon membrane depolarization in pituitary GH₃ cells, the exposure to SOL concentration-dependently increased the amplitude of M-type K⁺ current (I_K(M)) with effective EC₅₀ value of 0.34 μM. The activation time constant of I_K(M) was concurrently shortened in the SOL presence, hence yielding the K_D value of 0.55 μM based on minimal reaction scheme. As cells were exposed to SOL, the steady-state activation curve of I_K(M) was shifted along the voltage axis to the left with no change in the gating charge of the current. Upon an isosceles-triangular ramp pulse, the hysteretic area of I_K(M) was increased by adding SOL. As cells were continually exposed to SOL, further application of acetylcholine (1 μM) failed to modify SOL-stimulated I_K(M); however, subsequent addition of thyrotropin releasing hormone (TRH, 1 μM) was able to counteract SOL-induced increase in I_K(M) amplitude. In cell-attached single-channel current recordings, bath addition of SOL led to an increase in the activity of M-type K⁺ (K_M) channels with no change in the single channel conductance; the mean open time of the channel became lengthened. In whole-cell current-clamp recordings, the SOL application reduced the firing of action potentials (APs) in GH₃ cells; however, either subsequent addition of TRH or linopirdine was able to reverse SOL-mediated decrease in AP firing. In hippocampal mHippoE-14 neurons, the I_K(M) was also stimulated by adding SOL. Altogether, findings from this study disclosed for the first time the effectiveness of SOL in interacting with K_M channels and hence in stimulating I_K(M) in electrically excitable cells, and this noticeable action appears to be independent of its antagonistic activity on the canonical binding to muscarinic receptors expressed in GH₃ or mHippoE-14 cells.