A prospective cohort study on predictors of mortality of delirium in an emergency observational unit

Background: Delirium is often an underdiagnosed and underestimated neuropsychiatric syndrome, especially in low- and middle-income countries. Aim: To document the prevalence and clinical profile of delirium and to detect the baseline parameters associated with in-hospital mortality. Design: A prospective cohort study conducted between January 2016 to December 2016 at an adult medical emergency observational unit of an academic hospital in north India. Methods: Confusion Assessment Method for the intensive care unit was used for screening and diagnosis of delirium. Subtypes of delirium and severity were defined with the Richmond agitation-sedation scale and Delirium Rating Scale-Revised-98 (DRS-R-98). Results: Out of 939 screened patients, 312 (33.2%) had delirium, including 73.7% unrecognized cases. The mean age was 49.117.3years (range 17-90), and only 33.3% of the patients were above 60 years. The prevalence of hypoactive, mixed and hyperactive delirium was 39.1, 33.7 and 27.2%, respectively. Usual predisposing factors were alcohol use disorder (57.4%) and hypertension (51.0%), and infections remain the most common precipitating factors (42.0%). In total, 96.1% of patients received midazolam before delirium onset, and physical restraints were used in 73.4%. Mortality was higher in delirium (19.9% vs. 6.4%). The independent predictors of death in delirium were low diastolic blood pressure (P-value = 0.000), Glasgow coma scale score <15 (P = 0.026), high Acute Physiology and Chronic Health Evaluation II score (P = 0.007), high DRS-R-98 severity score (P = 0.000) and hyperactive delirium (P = 0.024). Conclusion: Rapid screening with Confusion Assessment Method for the intensive care unit detected a high prevalence of delirium (even in young patients), and it associated with high mortality.