Mini-Cog to Predict Postoperative Delirium in Patients Who Underwent Transurethral Resection of Bladder Tumor While Awake

In the postoperative management of transurethral resection of bladder tumor, attention should be paid to the appearance of delirium. Recently, the mini-cognitive assessment instrument (Mini-Cog) has been validated as a screening tool for cognitive impairment. We assessed whether positive preoperative cognitive impairment screening by Mini-Cog is associated with the occurrence of postoperative delirium. In this study, consecutive patients who underwent transurethral resection of bladder tumor while awake and were cognitively screened preoperatively using the Mini-Cog test at our institution were retrospectively analyzed. The relationship between the Mini-Cog test and clinical variables was examined. Univariate and multivariate analyses were carried out to determine the risk factors for the occurrence of postoperative delirium. Of the 193 included patients, 37 (19%) patients had probable cognitive impairment (Mini-Cog scores < 3). There were significant differences in patients' age (P < .001), Eastern Cooperative Oncology Group-physical status (P=.01), decline in instrumental activities of daily living from baseline (P=.03), preoperative diagnosis of dementia (P < .001), and use of benzodiazepine (P=.03) between the Mini-Cog score ≥ 3 group and the Mini-Cog score < 3 group. Multivariate analysis demonstrated that a Mini-Cog score < 3 (odds ratio=6.8, P < .001) and instrumental activities of daily living decline (odds ratio=3.0, P=.02) were independent risk factors for the occurrence of postoperative delirium. Screening of patients for cognitive function using the Mini-Cog test before transurethral resection of bladder tumor may allow for better identification of patients at risk of postoperative delirium.