Association between lactate-to-albumin ratio and postoperative delirium in elderly patients undergoing cardiac...

Postoperative delirium (POD) is highly prevalent among patients undergoing cardiac surgery, particularly in older adults. The lactate-to-albumin ratio (LAR), a composite biomarker reflecting both hypoxia and inflammatory pathways, could help elucidate the pathophysiological mechanisms underlying POD. This study aimed to determine the relationship between preoperative LAR and POD and to evaluate the potential predictive value of LAR.

This retrospective cohort analysis utilized data extracted from the Medical Information Mart for Intensive Care (MIMIC)-IV database. Patients eligible for inclusion were those ≥65 years of age and having received cardiac surgery. Hierarchical multivariable logistic regression assessed associations, controlling for multicollinearity (VIF) and modeling non-linearity (RCS). Predictive performance was evaluated using Youden index, AUC (DeLong), NRI, IDI, likelihood ratio tests and trend analysis.

This retrospective study analyzed data from 1770 elderly patients undergoing cardiac surgery. Of the 1770 patients, 412 (23.28%) developed postoperative delirium, and 131 (7.40%) died during hospitalization. Patients in the high LAR group had a 1.51-fold increased risk of POD compared to the low LAR group (adjusted OR=1.51, 95% CI 1.18-1.95, p < 0.005), and LAR as a continuous variable was independently associated with POD (adjusted OR=1.71 per unit increase, 95% CI 1.20-2.44, p = 0.003). After adjusting for confounding factors, this relationship was attenuated. Nevertheless, higher LAR remained independently associated with a higher risk of POD (all p< 0.05).

The results showed that a higher preoperative lactate/albumin ratio (LAR) was independently associated with an increased risk of postoperative delirium (POD) in elderly patients undergoing cardiac surgery, and that there was a non-linear relationship between LAR and the incidence of POD.