Postoperative Delirium is a Risk Factor of Poor Evolution Three Years After Cardiac Surgery: An Observational Cohort Study

Abstract

Background: After cardiac surgery, postoperative delirium (POD) is common and is associated with long-term changes in cognitive function. Impact on health-related quality of life (QOL) and long-term dependence are not well known. This aim of this study is to evaluate the role of POD in poor evolution at three years after surgery including poor QOL and dependence and mortality.

Patients and methods: We enrolled and followed 173 patients 60 years of age or older who were planning to undergo cardiac surgery with cardiopulmonary bypass. The primary composite outcome was death of any causes, or patients with either a loss of QOL (evaluated with of EuroQuol verbal 5D EQ5D less than 50), or a loss of two points on the instrumental activities of daily living occurring three years after surgery. POD was diagnosed with the use of Confusion Assessment Method. Multivariate logistic regression was performed.

Results: At three years, 74 patients (42.8%) had a poor evolution. Independent risk factors in poor patient evolution were sex (female gender; OR: 3.6; 95%CI: 1.45-8.7; p=0.006), metabolic status (diabetic patients; OR: 4; 95%CI: 1.6-10.2; p=0.002), Euroscore 2 (Euroscore 2 >1.5; OR: 5.2; 95%CI: 1.7-15.4; p=0.003) and POD (OR: 3.3; 95%CI 1.4-7.8; p=0.006). Coronary disease was protective (OR: 0.3; 95%CI: 0.14-0.71; p=0.006).

Conclusion: After cardiac surgery, POD significantly altered patient evolution and increased risk of dependence and loss of QOL.

Keywords: cardiac surgery; delirium; dependence; mortality; quality of life.

Figure 1

Kaplan–Meier time-to-event curves show the cumulative incidence of death from any cause among patients who present or not a postoperative delirium. At three years after the surgery, 56.7% of the postoperative delirium patients vs 30.8% in the control group (Wilcoxon test: p=0.005).