Abstract: Objective To assess the predictive value of preoperative sleep disturbance and nutritional status in postoperative delirium (POD) in elderly patients with colorectal cancer(CRC). 
Methods A total of 276 elderly patients who underwent radical colon cancer surgery in our hospital from January 2019 to December 2022 were retrospectively included, and were divided into the POD group (n=66, 23.91%) and the control group (n=210, 76.09%)according to development of POD at 7 d postoperatively. The clinical data of CRC patients were collected through the inpatient electronic medical record system, and the risk factors for the development of POD in elderly CRC patients were analyzed using a multivariate logistic regression method. The clinical efficacy of preoperative sleep disturbance and nutritional status for predicting POD was evaluated using receiver operating characteristic (ROC) curves. 
Results Univariate analysis showed that compared with the control group, the POD group had a significantly higher proportion of patients with age >70 years (68.18% vs. 48.57%), history of cerebrovascular disease (31.82% vs. 17.62%), TNM stage Ⅲ (43.94% vs. 29.52%), preoperative sleep disorders (59.09% vs. 34.76%), preoperative moderate to severe malnutrition (53.03% vs. 29.52%), and significantly prolonged duration of anaesthesia ［(4.29±1.13) h vs. (3.92±0.86) h］, with a significant difference (P＜0.05). Multivariate Logistic regression analysis showed that age >70 years (OR=1.390, 95%CI: 1.062-1.819), preoperative sleep disturbance (OR=1.752, 95%CI: 1.302-2.359), and preoperative moderate to severe malnutrition (OR=1.891, 95%CI: 1.256-2.846) were independent risk factors for elderly CRC patients combined with POD. The ROC curve showed that the area under the ROC curve (AUC) of preoperative sleep disturbance combined with moderate to severe malnutrition in predicting the development of POD in elderly CRC patients was 0.735, with sensitivity of 89.39% and specificity of 57.62% . 
Conclusion Preoperative sleep disturbance and malnutrition are independent risk factors for the development of POD in elderly CRC patients, and the combined detection can predict the risk of POD, to assist in the optimization of perioperative management and reduce the incidence of POD. 

Key words: colorectal neoplasms, delirium, sleep disturbance