Delirium During Acute Events in Nursing Home Patients

Assess the frequency of delirium during any acute event, its risk factors, and the duration of delirium in nursing home patients.

Prospective 2-month follow-up study.

145 nursing home patients living in 3 Norwegian nursing homes.

At baseline, known risk factors for delirium were obtained from medical records. During any acute events where the nurses decided that a physician had to be alerted, the Confusion Assessment Method was used to identify delirium on days 1, 2, 4, and 6 and thereafter weekly if delirium was present on day 6. The precipitating cause of delirium was registered based on diagnostics performed and treatment given.

One or more acute events occurred in 57 patients, and 34 (60%) of these patients developed delirium. In 91% of the patients with delirium, the delirium was present when the physician was alerted about the acute change. Delirium lasted for more than 1 week in 15 of the 34 patients. In 18 of the 34 patients with delirium, an infection was its precipitating factor. Regular use of benzodiazepines and a diagnosis of vascular dementia were significantly associated with delirium in the logistic regression model adjusted for age, number of drugs, and comorbidity [adjusted odds ratio (95% confidence interval) 3.75 (1.44-9.74) and 5.59 (1.53-20.43), respectively].

Acute events and illness were common in nursing home patients, and in our study, 60% had delirium associated with the event. In 9 of 10 patients, the delirium was present when the physician was alerted about the acute change, and infection was the most frequent cause of the delirium. Regular use of benzodiazepines and a diagnosis of vascular dementia were independent predisposing factors for delirium.