Sex specific differences in short-term mortality after ICU-delirium

Introduction: Delirium is a frequent complication in critically ill patients and is associated with adverse outcomes such as long-term cognitive impairment and increased mortality. It is unknown whether there are sex-related differences in intensive care unit (ICU) delirium and associated outcomes. We aimed to assess sex-specific differences in short-term mortality following ICU-delirium.

Methods: We conducted a retrospective cohort study using the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. Adult ICU patients who were diagnosed with delirium using the Confusion Assessment Method for the ICU (CAM-ICU) were included. The primary outcome was 30-day mortality following delirium onset. To control for baseline differences in demographics, illness severity, and comorbidities, we applied 1:1 propensity score matching. Cox proportional hazards regression models were used to evaluate the association between sex and mortality.

Results: A total of 8950 ICU patients with delirium were analyzed, of whom 42.6% were women. In univariable analysis, women had higher crude mortality (26.0% vs. 23.4%; HR 1.16, 95% CI 1.071-1.267, p < 0.001). After propensity score matching, the cohort included 3811 women and 3811 men. In adjusted analysis, risk for thirty-day mortality remained higher in women (HR 1.16, 95% CI 1.064-1.273, p < 0.001).

Conclusion: Our study suggests that women with ICU-delirium have a significantly higher risk of short-term mortality than men. Acknowledging the limitations inherent to observational studies with potential for residual confounding, further research is needed to understand the biological and clinical factors driving this disparity and to inform sex-specific interventions for ICU-delirium.