Postoperative delirium is a common complication of major surgery and of particular threat to older adults. It is related to increased short- and long-term morbidity and mortality and other serious surgical outcomes. A meta-analysis was undertaken to further understand the risk factors for delirium in patients undergoing gastrointestinal surgery.

Researchers included 21 case-control and cohort studies with a total of 6,265 participants in the analysis. The pooled incidence of delirium was 11%.

Of the 16 risk factors identified, 11 were associated with increased incidence of postoperative delirium: age, male sex, alcohol consumption, cerebrovascular disease, cardiovascular disease, use of sleeping pills, history of delirium, preoperative C-reactive protein levels, operation time, blood loss, and perioperative blood transfusion. By contrast, smoking, American Society of Anesthesiologists score, performance status, diabetes, and operation approach weren't significant risk factors.

The authors point out that some of the studies included in the analysis weren't of high quality, which reduces the credibility of the meta-analysis. Furthermore, there were shortcomings in the statistical methods used in the present study.