Association of Low Skeletal Muscle Mass and Low Skeletal Muscle Radiodensity With Postoperative Delirium in Patients Undergoing Off-Pump Coronary Artery Bypass Grafting: A Retrospective Cohort Study.

OBJECTIVES: To evaluate the correlation between low skeletal muscle index (SMI) and low skeletal muscle radiodensity (SMD) with the incidence of postoperative delirium (POD) in patients subjected to off-pump coronary artery bypass grafting (OPCABG). DESIGN: A single-center, retrospective observational study. SETTING: A university-affiliated hospital. PARTICIPANTS: The study cohort comprised 228 adult patients undergoing OPCABG between January and December 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Preoperative computed tomography scans were analyzed at the third lumbar vertebra to calculate SMI and SMD. Thresholds for low SMI and low SMD were established based on sex-specific distributions, with values falling into the lowest tertile classified as low. POD was evaluated throughout the recovery period utilizing either the Confusion Assessment Method for the Intensive Care Unit or the 3-Minute Diagnostic Interview for the Confusion Assessment Method. Of the 228 enrolled patients, 54 (23.7%) developed POD. Multivariable regression models identified both continuous SMI and SMD as independent predictors of POD (SMI: odds ratio [OR], 0.95; 95% confidence interval [CI], 0.90-0.999; SMD: OR, 0.93; 95% CI, 0.87-0.99). Notably, individuals with concomitant low SMI and low SMD faced a substantially heightened risk of POD (OR, 3.83; 95% CI, 1.35-10.84), although the broad confidence intervals observed in this subgroup analysis likely reflect the limited number of patients within this specific category. CONCLUSIONS: Among patients undergoing OPCABG, low SMI and low SMD were independently connected to POD. Additionally, the highest risk of POD was observed in patients with both low SMI and low SMD.