Alzheimer's disease and related dementias risk: Comparing users of non-selective andM3-selective bladder antimuscarinic drugs

Purpose Bladder antimuscarinic (BAM) drug use is associated with increased risk of Alzheimer's disease and related dementias (ADRD). It is hypothesized that BAMs with non-selective receptor binding may increase ADRD risk more than M3-selective BAMs. This study compared ADRD risk for users of non-selective and M3-selective BAMs and examines ADRD risk associated with overall BAM use. Methods Retrospective cohort study of Medicare claims for 71 688 individuals who used BAM drugs during 2007-2009 without an ADRD diagnosis. We compared ADRD incidence (2011-2016) between non-selective BAM users (fesoterodine, flavoxate, oxybutynin, tolterodine, trospium) and M3-selective BAM users (darifenacin, solifenacin). Logistic regressions compared individuals using target drugs in the same category of total standardized daily doses (TSDD) as a standardized measure of drug exposure, and adjusted for age, sex, race/ethnicity, healthcare utilization, other medication use, socioeconomic status, and comorbidities. Secondary analyses compared ADRD risk associated with different doses of BAMs overall. Results Non-selective BAM use (compared to M3-selective) was not significantly associated with ADRD incidence. Odds ratios for non-selective use were 0.97 (CI: 0.89-1.04) for 1-364 TSDD, 0.94 (CI: 0.83-1.06) for 365-729, 1.00 (CI: 0.87-1.16) for 730-1094, and 1.03 (CI: 0.88-1.20) for >1094. Higher TSDD of BAMs overall (combining both non-selective and M3-selective BAMs), when compared to 1-364 TSDD, were associated with increased ADRD incidence (OR = 1.05 (CI: 0.99-1.10) for 365-729, OR = 1.11 (CI: 1.05-1.17) for 730-1094, and OR = 1.10 (CI: 1.04-1.15) for >1094). Conclusions Non-selective and M3-selective BAM users had similar odds of ADRD incidence, and BAM use overall was significantly associated with ADRD incidence.