A Prospective Nested Case-Control Study of Risk Factors for Postoperative Delirium in Elderly Patients with Colorectal Cancer.

Purpose: The objective of this study is to investigate the risk factors associated with postoperative delirium (POD) in elderly patients diagnosed with colorectal cancer (CRC).

Patients and methods: This prospective nested case-control study included elderly patients who underwent CRC surgery at Shanxi Provincial Cancer Hospital between May 2022 and September 2023. A propensity score matching (PSM) method was employed to match patients by age and sex. Univariate and multivariate logistic regression analyses were conducted to identify independent risk factors for POD among elderly patients with CRC.

Results: A total of 443 patients were enrolled, among them, 70 (15.8% of all patients, age: 69.5[64, 73], 55 [78.6%] males) developed POD and 373 did not develop POD (84.2% of all patients, age: 67[62, 71], 234 [62.7%] males). Following PSM at a 1:3 ratio, 70 POD patients and 210 age- and sex-matched non-POD patients were selected for further analysis. The POD group exhibited a significantly higher sleep quality score (9 [6, 15] vs 7.5 [3, 12], P = 0.004), greater intraoperative infusion volume (2041.43±724.37 vs 1814.05±653.83, P = 0.015), and elevated peak pain levels post-surgery (1 [0, 2] vs 1 [0, 1], P = 0.001). Univariate and multivariate logistic regression analyses identified higher education level (OR: 0.503 [0.259-0.977]) as an independent factor associated with lower POD risk, whereas higher sleep quality scores (OR: 1.103 [1.040-1.171]) and increased peak pain levels post-surgery (OR: 1.727 [1.295-2.304]) were identified as independent risk factors.

Conclusion: Elevated peak postoperative pain levels, lower education levels, and sleep dysfunction or disturbance are independent risk factors for developing POD.