Mini-mental state examination (MMSE) score is a predictor of postoperative delirium in hemodialysis patients: preliminary study

Preoperative risk assessment for delirium after major surgery is important, because postoperative delirium prolongs the duration of hospital stay and is associated with an increased risk of death. However, no reports have assessed risk factors for the development of postoperative delirium in hemodialysis patients. Here, we investigated whether preoperative mini-mental state examination (MMSE) score is a predictor of delirium after major surgery in hemodialysis patients. A total of 47 hemodialysis patients who underwent major surgery under general anesthesia were included. MMSE was assessed preoperatively and analyzed for an association with the development of postoperative delirium. Evaluation showed that 23.4% of patients developed postoperative delirium, and the postoperative delirium group (n = 11) had significantly lower MMSE scores than the non-delirium group (n = 36) (26.3±3.2 vs 22.7±4.7, p = 0.006). Multivariate analysis adjusted for age, past history of cerebrovascular disease, serum albumin, hemoglobin and C-reactive protein showed that low MMSE score was an independent risk factor for postoperative delirium development (exp (β) = 0.690, 95% CI: 0.514 to 0.927, p = 0.014). Although further accumulation of cases is needed, our data suggests that preoperative MMSE score is a predictor of delirium after major surgery in hemodialysis patients.