The Reliability and Validity of the Chinese Version of Confusion Assessment Method Based Scoring System for Delirium...

Previous studies showed that the Confusion Assessment Method based delirium severity evaluation tool (CAM-S) had good reliability and validity. However, there is no Chinese version of the CAM-S. Therefore, we set out to perform a prospective investigation in older Chinese patients who had total joint replacement surgery under general anesthesia in Tenth People's Hospital in Shanghai, P.R. China. A total of 576 participants, aged 60 years or older, were screened, 179 participants were enrolled, and 125 of them were included for the final analysis. Pre-operative evaluations were conducted one day before the surgery. Postoperative evaluations were conducted twice daily from postoperative day 1 to day 3. The incidence of postoperative delirium was 24.8%. The Chinese version of CAM-S [including a Short Form (CAM-S Short Form) and a Long Form (CAM-S Long Form)] had an optimal reliability reflected by internal consistency (Cronbach's α= 0.748 and 0.839 for CAM-S Short Form and CAM-S Long Form respectively), split-halves reliability (Pearson correlation coefficient = 0.372 and 0.384 for CAM-S Short Form and CAM-S Long Form respectively), and inter-rater reliability (intra-class correlation coefficients = 0.629 and 0.945 for CAM-S Short Form and CAM-S Long Form respectively). Additionally, the Chinese version of CAM-S also showed a good discriminate validity. The domain scores of CAM-S were inversely correlated with corresponding domain scores of the MMSE. Finally, a receiver operating characteristic (ROC) analysis obtained an optimal cutoff point of 2.5 for CAM-S Short Form and 3.5 for CAM-S Long Form in recognizing delirium diagnosed by CAM. The areas under the ROC were 0.989 (95% CI 0.972 - 1.000, p < 0.001) and 0.964 (95% CI 0.946 - 0.982, p < 0.001), respectively. These data suggest that the Chinese version of CAM-S has good reliability and validity in evaluating postoperative delirium in geriatric Chinese patients and may be a useful tool to assess the severity of delirium.