Delirium and Long-Term Outcomes among Survivors of Extracorporeal Membrane Oxygenation Therapy: A Nationwide Cohort Study in South Korea

Background: The prevalence of delirium and its association with long-term outcomes of extracorporeal membrane oxygenation (ECMO) therapy have not yet been identified. We aimed to investigate the prevalence of delirium and its associated factors during hospitalization among ECMO survivors. We also examined whether the occurrence of delirium was associated with 1-year all-cause mortality among ECMO survivors. Methods: As a population-based cohort study, data were obtained from the National Health Insurance Service database in South Korea. Adults older than 18 years who received ECMO therapy between 2005 and 2018 were included in this study. ECMO survivors were defined as patients who were discharged from the hospital. Results: The analysis included a total of 8153 ECMO survivors, of whom 551 (6.8%) experienced delirium during hospitalization. Older age (odds ratio [OR]: 1.01, 95% confidence interval [CI]: 1.00-1.02; P = 0.004), male sex (OR: 1.38, 95% CI: 1.13-1.68; P = 0.002), underlying depression (OR: 1.90, 95% CI: 1.49-2.41; P < 0.001), and longer length of hospital stay (OR: 1.02, 95% CI: 1.02-1.03; P < 0.001) were associated with a higher incidence of delirium. In multivariable Cox regression modeling, the occurrence of delirium was not significantly associated with the risk of 1-year all-cause mortality (hazard ratio: 0.90, 95% CI: 0.76-1.07; P = 0.229). Conclusion: The prevalence of delirium among ECMO survivors during hospitalization was 6.8% in South Korea, and old age, male sex, longer duration of hospital stay, and underlying depression were associated with it. However, there was no significant association between delirium and 1-year all-cause mortality among ECMO survivors.