Impact of income levels on the prevalence of delirium: A secondary analysis of the World Delirium Awareness and Quality Survey in 2023

Background Delirium is associated with functional decline and reduced quality of life. While multiple risk factors have been identified, the relationship between national income level and delirium prevalence remains unclear. Aim To examine the association between country income level and delirium prevalence. Methods We performed a secondary analysis of the World Delirium Awareness and Quality Survey (WDAD2023), a one-day international cross-sectional epidemiological study. Delirium prevalence was assessed twice daily in wards or ICUs and compared between high-income and non-high-income countries. The primary outcome was median ward/unit delirium prevalence. Secondary outcomes included differences in delirium management practices. Multivariable analyses were conducted to adjust for these factors. Results Of 1,664 responses, 1,344 were analysed. Non-high-income countries included 159 facilities in 17 countries, and high-income countries included 1,185 facilities in 24 countries. Median ward/unit delirium prevalence was higher in non-high-income countries both in the morning (16.7% vs 11.1%, p < 0.01) and evening (20.0% vs 11.1%, p < 0.01). Management practices differed significantly between groups. In exploratory multivariable analyses, non-high-income status was associated with higher delirium prevalence after adjustment for potential confounding factors (p < 0.01). Conclusions and Relevance: Country income level might be associated with delirium prevalence. The development of specific delirium protocols for countries with low resources should be considered and evaluated.