Factors associated with persistent delirium after intensive care unit admission in an older medical patient population

Purpose: This study was designed to identify factors associated with persistent delirium in an older medical intensive care unit (ICU) population. Materials and Methods: This is a prospective cohort study of 309 consecutive medical ICU patients 60 years or older. Persistent delirium was defined as delirium occurring in the ICU and continuing upon discharge to the ward. The Confusion Assessment Method was used to assess for delirium. Patient demographics, severity of illness, and medication data were collected. Univariate and multivariate analysis were used to assess factors associated with persistent delirium. Results: Of 309 consecutive admissions to the ICU, 173 patients had ICU delirium, survived the ICU stay, and provided ward data. One-hundred patients (58%) had persistent delirium. In a multivariable logistic regression model, factors significantly associated with persistent delirium included age more than 75 years (odds ratio [OR], 2.52; 95% confidence interval [CI], 1.23-5.16), opioid (morphine equivalent) dose greater than 54 mg/d (OR, 2.90; 95% CI, 1.15-7.28), and haloperidol (OR, 2.88; 95% CI, 1.38-6.02); change in code status to "do not resuscitate" (OR, 2.62; 95% CI 0.95-7.35) and dementia (OR, 1.93; 95% CI 0.95-3.93) had less precise associations. Conclusions: Age, use of opioids, and haloperidol were associated with persistent delirium. Further research is needed regarding the use of haloperidol and opioids on persistent delirium.