Prevalence and Risk of Behavioral Symptoms among Patients with Insomnia and Alzheimer's Disease: A Retrospective Database Analysis

Abstract

Objectives: This study evaluated the prevalence and patterns of behavioral symptoms, including agitation/aggression (AA), psychotic symptoms (PS), anxiety/mood disorders (MD), and delirium among patients with Alzheimer's disease (AD) and their association with diagnosed insomnia.

Design: A retrospective cohort analysis was conducted using the MarketScan Multi-State Medicaid Database 2016-2020.

Setting and participants: Patients aged ≥50 with newly diagnosed AD (N = 56,904) were identified during 2017-2019 and categorized into insomnia and non-insomnia groups based on billing codes recorded in medical and pharmacy claims.

Methods: The index date was defined as the earliest date of diagnosis/medication of insomnia. The new diagnosis of AD had to be established within 12 months before (baseline) or 3 months after the index date. Point prevalence of behavioral symptoms was estimated during baseline and the 12-month follow-up period. Propensity score matching was performed to match patients with and without insomnia. Multivariable conditional logistic regression was used to assess the risk of diagnosis of behavioral symptoms among insomnia and non-insomnia groups.

Results: The study cohort included 7808 patients with newly diagnosed AD (mean age = 79.4, SD = 9.6 years). The point prevalence of behavioral symptoms was as follows: among those with insomnia (n = 3904), in the baseline, AA = 9.0%, PS = 12.5%, and MD = 57.8%, and during the follow-up, AA = 13.9%, PS = 16.3%, and MD = 72.1%; among those without insomnia (n = 3904), in the baseline, AA = 6.2%, PS = 9.2%, and MD = 41.4%; and during the follow-up, AA = 7.4%, PS = 10.4%, and MD = 49.2%. The likelihood of being diagnosed with any behavioral symptoms in the follow-up period was significantly higher among patients with insomnia than those without [adjusted odds ratio (OR), 2.7; 95% confidence interval (CI), 2.4-3.1].

Conclusions and implications: In patients with AD, prevalence of behavioral symptoms and likelihood of being diagnosed with behavioral symptoms were significantly higher among patients with diagnosed insomnia. Further investigation is needed to understand the relationship between insomnia and behavioral symptoms in patients with AD.

Keywords: Alzheimer's disease; behavioral symptoms; insomnia.