The scientific evidence is irrefutable—delirium in the intensive care unit is an independent predictor of death and acquired dementia.1 2 The linked study by Van den Boogaard and colleagues (doi:10.1136/bmj.e420) is the largest study on delirium in intensive care to date, and it provides a risk model to determine the likelihood of patients in intensive care developing delirium.3 The model (PRE-DELIRIC), which determines 10 risk factors, was developed and validated at the Radboud University Nijmegem Medical Centre in the Netherlands. It was then externally validated at four other Dutch hospitals. The risk model showed a high predictive value, and it was significantly better than the predictions of doctors and nurses.

Reassuringly there are no surprises; risk factors that confer the highest risk are coma with any cause, sedatives, and infection. Notably there were too few patients with alcohol dependency or dementia for these subgroups to be included in the model. However, a prediction model is not needed to confirm that these patients have a high risk of delirium because alcohol dependency and cognitive impairment are significant risk factors in any clinical setting,4 and both are non-modifiable.

Risk prediction models …