Association Between Postoperative Delirium and 12-month Mortality in Patients Undergoing Cardiac Surgery: Results from the Prospective Observational FINDERI Study

Background: Postoperative delirium (POD) affects 20 to 50% of individuals following cardiac surgery. POD is associated with considerably increased morbidity and a 30-day mortality of 7 to 10%, compared with 1% in patients without POD. The aim of this analysis was to identify associations between POD and other perioperative factors with all-cause mortality at 12 months in patients who underwent cardiac surgery.

Methods: We analyzed patients aged ≥50 years undergoing an elective cardiac surgery from the prospective observational FINd DElirium RIsk factors (FINDERI) study. The primary outcome was all-cause mortality at 12 months. Predictors included presurgical sociodemographic factors, baseline mild cognitive impairment (MCI, assessed using the Montreal Cognitive Assessment), surgical risk (American Society of Anesthesiologists [ASA] score), incidence of POD (assessed using the Confusion Assessment Method), and surgery-related characteristics. The outcomes were assessed at baseline (before surgery), during the first 5 postoperative days (POD), and at 12-month follow-up (mortality). To identify potential factors associated with 12-month mortality, we used a multiple Cox regression analysis.

Results: We analyzed data from 487 patients (68.3 ± 8.3 years, 22% females), of whom 100 screened positive for POD (21%). At 12-month follow-up, the overall mortality was 4.9%. Compared with non-survivors, survivors had a lower occurrence of POD (52.4% versus 19.6%, p < 0.001), baseline age (73.2 ± 7.7 versus 68.1 ± 8.2, p = 0.004), percentage of female sex (50% versus 20.5%, p = 0.002), preoperative MCI (87.5% versus 60.5%, p = 0.015), and ASA score (3.1 ± 0.5 versus 2.9 ± 0.6, p = 0.027), respectively. In the multiple Cox regression analysis, occurrence of POD (hazard ratio, HR 2.82, 95% CI 1.10, 7.19, p = 0.030), female sex (HR 3.17, 95% CI 1.27, 7.90, p = 0.014), and combined surgical procedure (HR 4.97, 95% CI 1.57, 15.8, p = 0.007) were independently associated with 12-month mortality. In this Cox regression model, there were no associations between baseline age, preoperative MCI, use of cardiopulmonary bypass, duration of surgery, or ASA score and 12-month mortality.

Conclusion: The occurrence of POD is an independent risk factor for 12-month mortality even when controlled for baseline age, preoperative MCI, and surgical factors. These findings highlight the clinical relevance of POD prevention strategies to reduce POD risk and occurrence in individuals undergoing cardiac surgery.

Publication History

Article published online:
11 February 2025