Incidence and risk factors of subsyndromal delirium after curative resection of gastric cancer

Background: Subsyndromal delirium, a condition in which patients exhibit some, but not all, of the symptoms of delirium, can negatively affect the outcomes of patients with cancer. However, the incidence of subsyndromal delirium in patients with gastric cancer is unknown. Here, we investigated the incidence and risk factors of subsyndromal delirium after curative resection of gastric cancer. Methods: We recruited consecutive patients with gastric cancer who were scheduled for curative resection at a tertiary hospital. Patients' subsyndromal delirium symptoms were serially assessed preoperatively and 1, 2, 3, and 7days postoperatively using the Delirium Rating Scale-Revised-98 (DRS-R-98). A DRS-R-98 score of 8-14 at any postoperative assessment was considered to indicate subsyndromal delirium. Sociodemographic and pre-/intra-operative clinical data were also assessed. Logistic regression analyses were used to determine the associated risk factors. Results: Data were analysed from 163 out of 217 eligible patients. Postoperative delirium occurred in one patient (0.6%) and subsyndromal delirium occurred in 19 patients (11.7%). Age≥70years (odds ratio, [OR] 3.85; 95% confidence interval [CI], 1.36-10.92; p=0.011) and education level≤9years (OR, 3.98; 95% CI, 1.39-11.41; p=0.010) were independent risk factors of subsyndromal delirium after adjusting for preoperative cognitive function. Other pre-/intra-operative variables including anxiety/depression, poor sleep quality, and anaesthesia duration were not associated with subsyndromal delirium. Conclusions: In contrast to the low incidence of delirium among patients undergoing curative resection of gastric cancer, a substantial proportion of such patients experienced subsyndromal delirium. Considering the prognostic implications, more careful detection and management of subsyndromal delirium may be warranted in patients with gastric cancer.