(428) The Relationship Between Geographic Disadvantage and ICU Delirium Characteristics

Introduction: Delirium is a disorder of fluctuating inattention that commonly occurs in critically ill patients and is a known risk factor for increased mortality and poor clinical outcomes. Geographic disadvantage has been associated with higher delirium incidence and severity in older postoperative patients, but this association has not been studied in ICU patients.

Methods: This was a secondary analysis of data collected from an NIH-funded clinical trial, the Pharmacologic Management of Delirium study. Patients ≥18 years of age admitted to the ICU for at least 24 hours and who developed delirium during their ICU stay were included. Patients with severe mental illness, pre-existing cognitive impairment, severe neurologic injury, or alcohol-related delirium were excluded. The Area Deprivation Index (ADI), a composite measure of geographic disadvantage derived from U.S. Census Bureau data, was obtained as a national percentile score for each patient’s address. Delirium duration was assessed by the number of delirium- and coma-free days (DCFDs). Delirium severity was assessed by the mean CAM-ICU-7 score. Each delirium outcome was assessed daily until hospital discharge. The sample was divided into quintiles based on ADI, and ANCOVA models were used to examine differences in DCFDs and CAM-ICU-7 scores between ADI quintiles while controlling for demographic and clinical variables.

Results: The study population included 322 patients: 54.5% were female and 48% black, with a mean age of 60.3 years, mean APACHE-II score of 20, and in-hospital mortality rate of 12.3%. The majority (52.2%) were admitted for acute respiratory failure or sepsis, with another 13.5% admitted for neurologic conditions, and 34.4% for other indications. The sample was heavily skewed toward higher national ADI percentile scores (indicating greater disadvantage); only 11.7% of patients had an ADI score lower than 50. Our regression analyses did not reveal any associations between ADI quintile and DCFDs or mean CAM-ICU-7 scores.

Conclusions: Our study did not find an association between geographic disadvantage and delirium duration or severity in ICU patients. However, the fact that most of our patients were from highly disadvantaged areas may have limited our ability to find an association.