Relation of serum cortisol to delirium occurring after acute coronary syndromes.

Background: Delirium can be associated with cardiac system disorders. Stress plays an important role in the pathogenesis of postoperative delirium. Cortisol is one of the most important stress hormones in humans. We aimed to investigate whether a relation exists between serum cortisol and the degree of delirium after acute coronary syndromes (ACS).

Methods: We enrolled 52 consecutive patients who presented with ACS and were hospitalized in the coronary care unit. Patients were examined daily by a single psychiatrist, and delirium was diagnosed by using the Delirium Rating Scale (DSR). Blood samples were obtained at 6:00 am of the next morning after admission.

Results: The mean age was 66 years (SD, ±6 years), and 52% were men. Delirium occurred in 25 patients (48%). The median score on the DRS was 17 for the delirious patients and 5 for the nondelirious. Median cortisol levels were significantly different between the delirium and nondelirium groups (13.9 vs 6.2 μg/dL; P < .01). There were significant correlations between the cortisol levels and the severity of the delirium based on DRS scores as well as between the cortisol levels and the presence of delirium (r = 0.65 and 0.74, respectively; P = .01). In a linear logistic regression model, cortisol predicted the occurrence of delirium (β = .81; P < .01). In receiver operating characteristics analysis, the optimal cutoff value of cortisol to predict delirium was 10.8 μg/dL, with 96% sensitivity and 89% specificity.

Conclusion: Delirium was common after ACS, and serum cortisol levels correlated with the degree of delirium and the risk of delirium.