Background: The overall evidence base regarding delirium has been growing steadily over the past few decades. There has been considerable analysis of delirium concerning, for example, mechanically ventilated patients, patients in the general intensive care unit (ICU) setting, and patients with exclusively postoperative delirium. Nevertheless, there are few studies regarding delirium in a cardiovascular ICU (ICCU) setting and especially scarce literature about the particular features of delirium relating to patient age and gender.

Aim: We aimed to determine particular features of delirium not induced by alcohol or other psychoactive substances, relating to patient age and gender in an ICCU setting.

Methods: An observational cross-sectional study was conducted to evaluate patients with delirium in a Lithuanian ICCU. From a sample of 19,007 ICCU admissions, 337 (1.8%) had documented delirium diagnosed through liaison and consultation with a psychiatrist and were included in the final analysis. The obtained data was then evaluated and analysed according to patients’ gender and four categorised age groups: < 65 years, 65–74 years, 75–84 years, and ≥ 85 years.

Results: Female patients who experienced delirium demonstrated a higher prevalence of hypertension, hyponatraemia, heart failure, cardiac rhythm and conduction disorders, myocardial infarction (MI), and dementia. The men, who were on average seven years younger than the women, significantly more often had hypokalaemia, double- or triple-vessel coronary artery disease, and sepsis. Furthermore, MI, ST-segment elevated MI, and Killip class 4 were most frequent amongst patients less than 65 years of age. Moreover, the youngest patient group demonstrated the highest mortality.

Conclusions: Our investigation presented a number of associated peculiarities related to gender and age. It was shown that delirium is a severe complication that more often affects men amongst patients < 65 years old and more frequently affects women in the age group of ≥ 85 years. Male patients < 65 years old, who develop delirium should be treated with more caution because they tend to have more serious forms of disorder and a poorer prognosis.