Risk Factors for Delirium in Hospitalized Patients With Medical Conditions Receiving Dual Orexin Receptor Antagonists

BACKGROUND: Dual orexin receptor antagonists (DORAs) demonstrate delirium-preventive efficacy in high-risk populations; however, delirium incidence under DORA treatment varies widely (0% to 43.8%). This study investigated factors associated with delirium development in older inpatients with insomnia disorder receiving DORAs. METHODS: This retrospective study included patients aged 65 years or above admitted between April 2019 and March 2023 who received DORAs following consultation-liaison psychiatric intervention. Patient characteristics, clinical conditions, and delirium risk factors-including major neurocognitive disorder or cerebrovascular disease, cognitive impairment, electrolyte abnormalities, alcohol history, prior delirium, surgical procedures, and concomitant medications-were extracted from medical records. Multivariable logistic regression analysis was performed using JMP 18. RESULTS: Among 406 patients [median age, 76 years (range, 65 to 102 y); 61.8% men], 116 (28.6%) developed delirium. Multivariate analysis identified 4 independent risk factors: advanced age (65 y or above) [adjusted odds ratio (aOR): 1.05 per year; 95% CI: 1.01-1.09; P < 0.001], potentially deliriogenic medications (aOR: 1.94; 95% CI: 1.07-3.50; P = 0.03), benzodiazepine use (aOR: 2.19; 95% CI: 1.01-4.77; P < 0.05), and ramelteon co-administration (aOR: 2.85; 95% CI: 1.60-5.07; P < 0.001). CONCLUSIONS: Since concomitant medications represent modifiable risk factors, DORA monotherapy may be preferable for insomnia management in older hospitalized patients.