Emergency Department Length of Stay Is Associated with Delirium in Older Adults

INTRODUCTION: Incident delirium in older patients is associated with prolonged hospitalization and mortality. A recent study suggested an association between emergency department (ED) length of stay (LOS), time in ED hallways, and incident delirium. In this study we further evaluated the emerging association between incident delirium with ED LOS, time in ED hallways, and number of non-clinical patient moves in the ED. METHODS: We performed this retrospective cohort study at a single, urban, academic medical center. All data were extracted from the electronic health record. We included patients aged ≥65 years presenting to the ED and admitted to family or internal medicine services over a two-year period. Patients admitted to any other service, transferred from another hospital, discharged from the ED, or who underwent procedural sedation were excluded. The primary outcome was incident delirium, defined as a positive delirium screen, receipt of sedative medications, or use of physical restraints. Multivariable logistic regression models including age, gender, language, history of dementia, Elixhauser Comorbidity Index, number of non-clinical patient moves within the ED, total time spent in the ED hallway, and ED LOS were fitted. RESULTS: We studied 5,886 patients ≥65 years of age; median age was 77 (69-83) years; 3,031 (52%) were female, and 1,361 (23%) reported a history of dementia. Overall, 1,408 (24%) patients experienced incident delirium. In multivariable models, ED LOS was associated with development of delirium (odds ratio OR 1.02, 95% confidence interval CI 1.01-1.03, per hour), while non-clinical patient moves [OR 0.97, (95% CI 0.91-1.04) and ED hallway time [OR 0.99, 95% CI 0.98-1.01, per hour) was not associated with development of delirium. CONCLUSION: In this single-center study, ED length of stay was associated with incident delirium in older adults, while non-clinical patient moves and ED hallway time in the ED were not. Health systems should systemically limit time in the ED for admitted older adults.