OBJECTIVES: Acetylcholinesterase Inhibitor (AChEI)-associated adverse effect of urinary incontinence often leads to prescribing of antimuscarinics among patients with Alzheimer’s disease (AD), a phenomenon referred to as prescribing cascade. This study evaluated antimuscarinic prescribing cascade associated with AChEIs among older adults with AD.

METHODS: This retrospective cohort study included older adults (aged>=65 years) with a diagnosis of AD. The study used multi-year (2013-2015) Medicare claims data and included patients who received AChEIs versus those who did not (control). The index date for the study groups was the first prescription with six months of washout period. Prescribing cascade was defined as the receipt of an antimuscarinic medication within six months of initiating AChEI or control medication. Kaplan Meier analysis and Cox proportional hazards regression with inverse probability of treatment weighting (IPTW) compared antimuscarinic cascade in AChEI and control groups.

RESULTS: There were 102,555 older adults with AD, 87,027 (84.86%) received AChEIs while 15,528 (15.14%) did not. Among AChEI recipients, most were females (67.23%) and aged 75-84 years (44.34%). In the control group, most were females (66.81%) and aged 85-94 years (43.79%). A total of 1,532 (1.76%) patients in the AChEI group and 172 (1.11%) patients in the control group received an antimuscarinic within six months. Kaplan Meier analysis showed no significant difference in the risk of antimuscarinic cascade between AChEI and control groups (P-value = 0.983). The IPTW Cox regression also found no significant difference (HR = 1.02; 95% CI, 0.88-1.18) between AChEIs and control groups for the risk of receiving antimuscarinics.

CONCLUSIONS: The study found that there is no significant risk of antimuscarinic prescribing cascade with AChEIs among older adults with AD. Although previous studies found prescribing cascade associated with AChEIs, the low occurrence of antimuscarinic cascade could be attributed to increasing concerns of polypharmacy and anticholinergic use in older adults.