Fig. 2

Agreement between different delirium assessment methods and the neurological experts’ reference rating using the DSM-5 criteria. This figure shows the graphic representation of kappa coefficients and their standard deviations for each of the methods used to assess delirium. The kappa coefficient measured the agreement between each of the methods and the assessment by the neuropsychologist experts using DSM-5 criteria (reference standard). For simple questions, we did not decide a priori how to analyze the answers. Because some patients answered some questions but did not answer other ones, we decided a posteriori to analyze these data following two approaches: including all patients and including only the patients able to answer all the questions. Several thresholds were tested, i.e., delirium was defined in all patients if they gave at least 1 or 2 false or no response(s), or, among the patients who were able to answer all simple questions, if the patients gave at least 1 or 2 false response(s). There was a significant difference (p < 0.047) between the CAM-ICU and each of the other methods, except the ICDSC (p = 0.054). There were significant differences between “all methods from CAM-ICU to ≥ 1 false response to simple questions” and “patient’s own impression of feeling delirious,” as well as between “all methods from CAM-ICU to nurse diagnosis” and “≥ 2 false responses to simple questions” or “patient’s own impression of feeling delirious.” *: Significant difference (p < 0.05); CAM-ICU Confusion Assessment Method for the Intensive Care Unit, ICDSC Intensive Care Delirium Screening Checklist