An evaluation of single question delirium screening tools in older emergency department patients

To determine the diagnostic performances of several single question delirium screens. To the patient we asked: "Have you had any difficulty thinking clearly lately?" To the patient's surrogate, we asked: "Is the patient at his or her baseline mental status?" and "Have you noticed the patient's mental status fluctuate throughout the course of the day?"

This was a prospective observational study that enrolled English speaking patients 65 years or older. A research assistant (RA) and emergency physician (EP) independently asked the patient and surrogate the single question delirium screens. The reference standard for delirium was a consultation-liaison psychiatrist's assessment using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) criteria. All assessments were performed within 3 h and were all blinded to each other.

Of the 406 patients enrolled, 50 (12%) were delirious. A patient who was unable to answer the question "Have you had any difficulty thinking clearly lately?" was 99.7% (95% CI: 98.0%-99.9%) specific, but only 24.0% (95% CI: 14.3%-37.4%) sensitive for delirium when asked by the RA. The baseline mental status surrogate question was 77.1% (95% CI: 61.0%-87.9%) sensitive and 87.5% (95% CI: 82.8%-91.1%) specific for delirium when asked by the RA. The fluctuating course surrogate question was 77.1% (95% CI: 61.0%-87.9%) sensitive and 80.2% (95% CI: 74.8%-84.7%) specific. When asked by the EP, the single question delirium screens' diagnostic performances were similar.

The patient and surrogate single question delirium assessments may be useful for delirium screening in the ED.