OBJECTIVES: Limited literature exists on the effectiveness of individual acetylcholinesterase inhibitors (AChEIs) in managing behavioral symptoms of dementia that require antipsychotic therapy. This study compared the initiation of antipsychotic medications among older adults with dementia treated with donepezil, rivastigmine, or galantamine.

METHODS: This retrospective cohort study included older adults (aged>=65 years) with a diagnosis of dementia identified using ICD-9-CM codes. The study used multi-year (2013-2015) Medicare claims data involving Parts A, B, and D. The AChEIs included donepezil, rivastigmine, and galantamine while antipsychotics included typical and atypical agents. The study identified new users of AChEIs and followed them for up to 180 days for antipsychotic initiation. Descriptive statistics examined the demographic and clinical characteristics of the cohort. Multivariable Cox proportional hazards regression compared antipsychotic initiation among the three AChEIs adjusting for other risk factors.

RESULTS: The study identified 178,558 older adults with dementia who were new users of AChEIs. Most were females (67.28%), white (83.56%), and in the age group of 75-84 years (43.92%). A total of 23,469 (15.15%) donepezil users, 4,121 (19.06%) rivastigmine users, and 324 (15.77%) galantamine users initiated antipsychotics. The mean time to antipsychotic initiation among patients who received antipsychotics was 112.19 (±74.14) days for donepezil users, 96.00 (±72.40) days for rivastigmine users, and 105.90 (±77.14) days for galantamine users. The Cox regression analysis showed that rivastigmine (aHR=1.26; 95% CI, 1.19-1.33) was associated with a statistically significant increase in the risk of antipsychotic initiation as compared to donepezil; while there was no significant difference between galantamine and donepezil.

CONCLUSIONS: The study found that antipsychotics are commonly used along with AChEIs for managing behavioral symptoms of dementia. There was 26% increased risk of antipsychotic initiation among users of rivastigmine as compared to donepezil users. Further studies are needed to evaluate the impact of these effects in dementia patients.