Recurrent delirium episodes within the intensive care unit: Incidence and associated factors

Purpose: Describe the incidence and factors associated with recurrent delirium in the intensive care unit (ICU). Materials and methods: Retrospective study of ICU patients diagnosed with delirium. Delirium clearance defined as 48 h of negative delirium assessments following initial episode and recurrent delirium as any positive delirium assessment following clearance. Multivariable logistic regression model assessed independent association of patient and hospital factors on development of recurrent delirium, adjusting for pre-defined covariates.Results: Among 8591 ICU admissions identified with delirium, 1067 (12.4%) had recurrent symptoms. Factors associated with increased odds of recurrent delirium were age (nonlinear; p = 0.02), shock (OR 1.45, 95% CI [1.20, 1.75]), admission to medical (OR 3.25, 95% CI [2.42, 4.37]), surgical (OR 3.00, 95% CI [2.21, 4.06]), or trauma (OR 2.17, 95% CI [1.58, 3.00]) ICU vs. cardiovascular ICU, increased duration of mechanical ventilation (OR 2.43, 95% CI [2.22, 2.65]), propofol use (OR 1.35, 95% CI [1.02, 1.80]), and antipsychotic medications (haloperidol OR 1.53, 95% CI [1.26, 1.86]; quetiapine OR 2.45, 95% CI [1.98, 3.02]; and olanzapine OR 1.54, 95% CI [1.25, 1.88]).Conclusions: Over 10% of delirious ICU patients had recurrent symptoms. Factors associated with recurrence included age, duration of mechanical ventilation and medication exposure. Clinical Trial Number: Not applicable.