Delirium overlooked in hospital patients

By Eleanor McDermid, Senior medwireNews Reporter

Delirium occurs in about one in five inpatients, but appears to be a low priority with hospital staff, research suggests.

Niamh O'Regan (University College Cork, Ireland) and co-workers assessed the occurrence of delirium across an entire tertiary hospital during a single day, excluding patients in the emergency department, the intensive care unit, and isolation rooms, as well as those who were severely aphasic.

The rates of delirium among the 280 patients assessed were 19.6% according to Diagnostic and Statistical Manual of Mental Disorders-IV criteria, 17.6% with the Confusion Assessment Method, and 20.7% with the Delirium Rating Scale-Revised-98.

The researchers also spoke to nursing staff, who told them that 63.6% of patients in their care had shown symptoms of delirium at any time during their stay. Yet just 43.6% of patients had delirium recorded in their medical notes.

"Even if some recognised, but undocumented, delirium cases occurred, it suggests that delirium is not a high diagnostic and therapeutic priority, despite its treatability and relevance to outcomes, especially for poorer prognosis in the elderly," writes the team in BMJ Open.

Older age was a strong predictor for delirium, which occurred in 21.3% of patients aged 65-79 years and 34.8% of those aged 80 years or older, compared with just 4.7% of patients younger than 50 years.

"As the 'oldest old' segment of the population rapidly expands and hence accounts for a larger proportion of the acute hospital population, hospital delirium rates may increase even further," note O'Regan et al.

Dementia was also closely associated with delirium, with half of delirious patients having pre-existing dementia. However, dementia was mentioned in the case notes of just five of the 28 patients with the condition.

"Thus, if we overly focus delirium screening on patients with known cognitive impairment, we may miss cases unless practices for detecting cognitive impairment also improve," say the researchers.

Finally, the team says when considering education to improve delirium recognition, it is important to consider differences in how hospital staff detect the condition. Nursing staff tended to notice unusual behavior and delusions in the patients, whereas medical staff were more likely to notice short-term memory problems and inattention.

O'Regan et al say: "This may reflect the focus of the medical round: brief, direct questioning of patients, which may unmask attention and cognitive deficits."

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