Impact of delirium in cardiosurgical patients on short- and long-term mortality

Postoperative delirium (POD) is a common and serious complication in intensive care unit (ICU) patients after cardiac surgery. Its long-term impact remains uncertain. The aim was to determine the association between postoperative delirium and 8-year all-cause mortality in adult cardiac ICU patients.

This retrospective cohort study analysed patients admitted to a university hospital ICU following cardiac surgery. Data from pre-, peri-, and postoperative phases were collected. The primary outcome was mortality up to 8 years after ICU discharge. Secondary outcomes included POD incidence, ICU readmission, mortality at day 7 and 30 post-discharge, and ICU and hospital length of stay (LoS). Regression analyses were conducted to examine associations.

The study included 551 patients, predominantly male (71 %, n = 397), with a median age of 72 (IQR 64-77) years. POD was diagnosed in 18.7 % (n = 103). Overall, the 8-year mortality rate was 16.7 % (n = 92). Compared to non-POD patients, those with POD had significantly higher 6-8 years mortality (n = 9 (8.7 %) vs. n = 16 (3.6 %), p = 0.033). Patients with POD had a longer LoS in ICU (median 4 vs. 2 days, p < 0.001) and hospital (15 vs. 12 days, p < 0.001), as well as higher ICU readmission rates within 30 days (12.3 % vs. 6.6 %, p = 0.037). POD patients also showed higher mortality at 30 days (3.8 % vs. 0.9 %, p = 0.028). However, after adjusting for confounders, POD was no longer significantly associated with long-term 6-8 years mortality (p = 0.205).

POD affects nearly one in five patients after cardiac surgery and is associated with adverse short-term outcomes, including longer stays and higher readmission and early mortality rates. Its independent effect on long-term mortality may be limited. Further studies are needed to explore its influence on quality of life and cognitive function.