Do specific delirium aetiologies have different associations with death? A longitudinal cohort of hospitalised patients

Purpose: To describe aetiology-specific associations with mortality among older hospital patients with delirium. Methods: Over 21 months, a cohort of 1702 patients with 2471 acute hospital admissions (median age 85, IQR 80–90, 56% women) were assessed for delirium, categorised with inflammatory and metabolic aetiologies based on available laboratory results, and followed up for all-cause mortality. Interactions between aetiology and delirium were tested. Results: The total mortality for the cohort was 35.2%. While inflammation, metabolic disturbance, and delirium at time of admission all demonstrated independent associations with mortality, there was no evidence for any interactions between delirium and these laboratory-measured aetiologies. Conclusions: Delirium remains an important predictor of death in older hospital patients, irrespective of underlying aetiology.