Association Between ICD-Coded Delirium and Health Determinants in The Atherosclerosis Risk in Communities Study

Delirium is common among hospitalized adults, prevalence estimates ranging from 33% to 50% of hospitalized patients over age 65. Yet, little is known about the association between social determinants of health (SDOH) and delirium.

To describe neighborhood-level risk factors for hospitalization with delirium. We examined the association between hospitalization with delirium and neighborhood disadvantage, measured by the Area Deprivation Index (ADI)-a tool that measures SDOH by assessing socioeconomic conditions and disadvantages within a geographic area.

The Atherosclerosis Risk in Communities (ARIC) study is a community-based prospective cohort of adults recruited from four US communities. This analysis included ARIC participants that attended visit 5 (2011-2013) and had at least one hospitalization before visit 7 (2018-2019). Delirium was identified and quantified using hospital claim records. The association between ADI quartiles and incidence and number of delirium events was estimated with offset Poisson regression models for the time participants were observed. Associations were also examined by cognitive status.

In this analytic cohort of 4130 participants, 486 (11.8%) experienced at least one hospitalization with delirium. Unadjusted regression analyses showed a higher incidence of delirium (proportion ratio, PR = 1.32; and 95% CI = 1.03, 1.69) and number of delirium events (incidence rate ratio, IRR = 1.30; 95% CI = 1.05, 1.63) among participants from the highest ADI quartile compared to the lowest quartile. In fully adjusted models, this association was attenuated. Among participants with mild cognitive impairment (MCI) and dementia, those from the most disadvantaged neighborhoods experienced a higher incidence and number of delirium events.

In this cohort of hospitalized older adults, participants from more disadvantaged neighborhoods had a higher incidence of delirium; this association was attenuated in adjusted analyses. This suggests that neighborhood-level social disadvantage may be meaningful in studies on prevention and management of delirium, though overlapping demographic and clinical characteristics likely confound this relationship.