Risk factors for postoperative delirium in elderly patients with colorectal cancer

Aims The aim of this retrospective study is to examine risk factors for postoperative delirium in elderly patients with colorectal cancer. Methods The study subjects were patients aged 71 years and older who underwent open surgery (OS) or laparoscopically assisted surgery (LAS) for colorectal cancer from January 2004 to December 2007. Preoperative evaluation, operative factors, morbidity, and mortality were analyzed using the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM) and Prognostic Nutritional Index (PNI). Delirium was diagnosed by the Confusion Assessment Method (CAM). Results Postoperative delirium was diagnosed in 10.9% of elderly patients with colorectal cancer. Age, American Society of Anesthesiologists (ASA) score, and PNI were significantly higher in patients with delirium than those without (P < 0.05, each). Postoperative delirium occurred more frequently in patients with encephalopathy than in those without (P = 0.003). Logistic regression analysis identified PNI and encephalopathy as two independent risk factors for postoperative delirium. Conclusions Preoperative evaluation of nutritional status is important in elderly patients with colorectal cancer in order to prevent postoperative delirium.