Gender Differences in Neuropsychiatric Symptoms in Mild to Moderate Alzheimer's Disease Patients Undergoing Switch of Cholinesterase Inhibitors: A Post Hoc Analysis of the EVOLUTION Study

Background: Alzheimer's disease (AD) is characterized by progressive cognitive decline, often associated with Behavioral and Psychological Symptoms of Dementia (BPSD). Acetylcholinesterase inhibitors (ChEi) may attenuate cognitive decline and mitigate BPSD. The EVOLUTION group found that the switch from oral ChEi to transdermal rivastigmine patch formulation resulted in improvement/stabilization in the frequency of clinically relevant BPSD, but gender-specific subgroup analyses were not reported. Methods: Participants underwent Neuropsychiatric Inventory to assess the frequency and severity of neuropsychiatric symptoms at baseline and 3 and 6 months after the switch from oral ChEi to transdermal rivastigmine patch. A descriptive post hoc analysis was conducted to assess whether there were gender-based differences in BPSD profile during the 6 months after the switch. Results: The entire sample consisted of 475 patients, 274 women and 201 men. Women were on average slightly older and with poorer cognitive performance (60.6% of the women had moderate-AD, defined as Mini-Mental State Examination [MMSE] score of 10-17, vs. 43.8% of men). In mild-AD patients (MMSE score 18-26), the frequency of BPSD did not change significantly over time and an association was found between gender and depression (odds ratio; OR [95% confidence interval; CI] female vs. male=3.32 [1.44-7.67]), anxiety (2.42 [1.23-4.79]), apathy (2.25 [1.07-4.70]), nighttime behavior disturbances (3.97 [1.66-9.49]), and appetite/eating abnormalities (2.39 [1.10-5.18]). Moderate-AD female patients had euphoria more frequently than male patients (OR [95% CI] female vs. male=3.67 [1.25-10.74]). The frequency of delusions, anxiety, and irritability decreased during the first 3 months after the switch, independently of gender. Conclusion: Mild-AD women tended to suffer more frequently from BPSD than men; in the 3 months after treatment switch, moderate-AD patients showed a decrease in delusions, anxiety, and irritability, with no significant differences between genders. Ad hoc studies to investigate this potential gender effect in AD could be well worthwhile.