Incidence, prevalence, risk factor and outcome of delirium in intensive care unit: a study from India

To evaluate the incidence, prevalence, risk factors and outcome of delirium in the respiratory intensive care unit of a tertiary care hospital.

Consecutive patients admitted to an eight-bed respiratory intensive care unit were screened for presence of delirium by a psychiatrist. Patients found to have delirium were evaluated using univariate techniques for their clinical profiles, risk factors for delirium, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, duration of stay (in days) and outcome at discharge from intensive care unit besides evaluation on Delirium Rating Scale-Revised 98 version (DRS-R-98).

Incidence and prevalence rate of delirium were 24.4% and 53.6% respectively. Univariate analyses revealed that the prevalence of delirium was higher (64%) in mechanically ventilated patients. The predisposing risk factors identified for delirium in univariate analysis were higher age; higher Glasgow Coma Scale score; increased APACHE II score; hyperuricemia; hypoalbuminemia; presence of acidosis; abnormal alkaline transferase levels; use of mechanical ventilation; higher number of total medication received and use of sedative, steroids and insulin. Univariate analysis showed that patients who were diagnosed with delirium had significantly longer duration of intensive care unit (ICU) stay and higher mortality rates. Age, multiple organ failure, hypoactive delirium and higher DRS-R-98 scores were significant risk factors for mortality in patients with delirium.

Delirium is highly prevalent in the ICU setting and delirium is associated with longer ICU stay and higher mortality.