New-onset delirium during hospitalization in older adults: incidence and risk factors

Delirium is a clinical diagnosis that can occur frequently in hospitalized patients. A retrospective study was completed to identify the incidence of patients aged greater than 65 developing delirium during hospitalization.

This study was conducted at a single tertiary care teaching hospital. Charts of discharged patients from November to December 2018 were evaluated and patients less than age 65 or with delirium present on admission were excluded. The search terms altered, delirium, encephalopathy, and confusion were used to identify patients who developed delirium during the hospitalization. Characteristics of the patients with delirium were also collected.

The incidence of new-onset delirium in patients over age 65 during hospitalization was 10%. Patients who developed delirium during their hospital stay were found to have a higher risk of mortality (p = 0.0028) and severity of illness (p = 0.014). A strong correlation between the length of stay (LOS) and incidence of delirium was also noted.

The strong correlation between a longer LOS and a higher incidence of delirium should guide the development of new innovative strategies to shorten the LOS and thus reduce the risk of delirium, in high-risk older hospitalized patients.