Relationship between PCT, CRP, and IL-6 and postoperative delirium in ICU patients and its influencing factors

To investigate the relationship of procalcitonin (PCT), C-reactive protein (CRP), and interleukin-6 (IL-6) with postoperative delirium (POD) in intensive care unit (ICU) patients, and to identify influencing factors.

Based on POD occurrence, 120 postoperative ICU patients were split into delirium (n = 72) and non-delirium (n = 48) groups. Clinical data and post-operative 24-h serum PCT, CRP, and IL-6 levels were gathered. Pearson correlation assessed relationships between these inflammatory markers, delirium incidence, and DRS-R-98 scores. Multivariate logistic regression identified predictors, and ROC curves evaluated the predictive value of the inflammatory markers.

Delirium patients were older with higher APACHE II scores, more frequent mechanical ventilation, and longer ICU stays (P < 0.05). Their serum PCT, CRP, and IL-6 levels were higher and positively correlating with POD incidence and severity (DRS-R-98 scores) (r > 0, P < 0.05). These markers were identified as independent POD predictors (OR > 1, P < 0.05), demonstrating good predictive value with AUCs of 0.936 (CRP), 0.894 (PCT), and 0.820 (IL-6).

Postoperative inflammation serves as an independent risk factor for POD in ICU patients. Serum PCT, CRP, and IL-6 levels facilitate early detection and risk assessment, supporting preventive strategies and mitigating POD-related complications.