The stress hyperglycemia ratio as a novel risk marker for postoperative delirium after cardiac valve surgery

The stress hyperglycemia ratio (SHR) has been demonstrated to be associated with numerous adverse outcomes; however, its relationship with postoperative delirium (POD) in patients undergoing cardiac valve surgery remains unclear. This study aimed to investigate the association between SHR and POD in this surgical population. This retrospective study analyzed the data from 1830 adult patients who underwent cardiac valve surgery from the Medical Information Mart for Intensive Care IV (MIMIC-IV, version 3.1) database. Primary outcome was the incidence of POD within 7 postoperative days. Secondary outcomes included lengths of stay in the intensive care unit (ICU) and hospital, as well as 28-day and 90-day mortality. Multivariable logistic regression identified SHR as an independent risk factor for POD (odds ratio [OR] 1.47, 95% confidence interval [CI] 1.03-2.11, P = 0.034). Using the optimal SHR cutoff, patients were stratified into high-SHR (≥ 1.164) and low-SHR (< 1.164) groups. Those with high SHR had a significantly elevated risk of POD compared to the low-SHR group (OR 1.55, 95% CI 1.18-2.03, P = 0.002). Sensitivity analyses confirmed the robustness of these findings. After 1:1 propensity score matching based on key confounders, the high-SHR group also exhibited prolonged ICU stay and higher 28-day and 90-day mortality. No significant interactions were detected in any of the predefined subgroup analyses. These findings suggest that SHR is an important risk factor for POD following cardiac valve surgery and demonstrates considerable potential as a novel risk marker for POD in this surgical population.