Association between sleep disorder and delirium in adult patients undergoing cardiac surgery: a retrospective cohort study.

backgroundCompared to non-cardiac surgical patients, those undergoing cardiac surgery exhibit a higher prevalence of sleep disturbances and delirium, yet limited research has specifically examined this association in the cardiac surgical population. This study investigates the association between sleep disorders and the risk of delirium in patients after cardiac surgery, aiming to raise public awareness of the relationship.

methodsThis retrospective cohort study utilized data from the MIMIC-IV database. Patients were stratified by sleep disorder status. The primary outcome was delirium incidence, and the secondary outcome was the length of stay in ICU and hospital, and all-cause mortality. The propensity score matching (PSM) was performed to adjust for the baseline imbalances. Multivariate logistic regression analysis was used to evaluate the effect of sleep disorders on delirium. Survival outcomes were analyzed using Kaplan-Meier curves with log-rank tests and Cox proportional hazards models.

resultsThis study initially enrolled 6080 patients. After 1:3 matching, the final cohort consisted of 4188 patients, with 1047 assigned to the sleep disorder group and 3141 to the non-sleep disorder group. Sleep disorder was not a risk factor for postoperative delirium in either the primary cohort (odds ratio [OR]: 1.06, 95% CI: 0.86 ~ 1.29, p = 0.586) or the matched cohort (OR: 1.05, 95% CI: 0.86 ~ 1.29, p = 0.628). Ramelteon use in ICU increased the risk of delirium in the matched cohort (OR: 2.05, 95%CI: 1.36 ~ 3.09, p < 0.001). Notably, delirium prolonged the ICU stay (β:2.08, 95% CI: 1.97 ~ 2.20; p < 0.001) and hospital stay (β:1.30, 95% CI: 1.25 ~ 1.36, p < 0.001), and increased the risk of mortality at one year (HR: 1.89, 95%CI: 1.35 ~ 2.69, p < 0.001) and three years (HR: 1.56, 95%CI: 1.16 ~ 2.1, p = 0.003).

conclusionAlthough sleep disorders did not show significant associations with postoperative delirium in patients undergoing cardiac surgery based on MIMIC database, sleep screening should remain an integral part of a comprehensive perioperative risk assessment. Delirium is an independent risk factor for increased mortality and increased healthcare resource consumption. The core of clinical management should focus on early identification and efficient intervention of postoperative delirium. CLINICAL TRIAL NUMBER: Not applicable.