Predicting hospital mortality and length of stay: A prospective cohort study comparing the Intensive Care Delirium Screening Checklist versus Confusion Assessment Method for the Intensive Care Unit

Abstract

ObjectiveThe objective of this study was to compare two tools, the Intensive Care Delirium Screening Checklist (ICDSC) and Confusion Assessment Method for the intensive care unit (ICU) (CAM-ICU), for their predictive validity for outcomes related to delirium, hospital mortality, and length of stay (LOS). MethodsThe prospective study conducted in six medical ICUs at a tertiary care hospital in Taiwan enrolled consecutive patients (≥20 years) without delirium at ICU admission. Delirium was screened daily using the ICDSC and CAM-ICU in random order. Arousal was assessed by the Richmond Agitation–Sedation Scale (RASS). Participants with any one positive result were classified as ICDSC- or CAM-ICU-delirium groups. ResultsDelirium incidence evaluated by the ICDSC and CAM-ICU were 69.1% (67/97) and 50.5% (49/97), respectively. Although the ICDSC identified 18 more cases as delirious, substantial concordance (κ = 0.63; p < 0.001) was found between tools. Independent of age, Acute Physiology and Chronic Health Evaluation II score, and Charlson Comorbidity Index, both ICDSC- and CAM-ICU-rated delirium significantly predicted hospital mortality (adjusted odds ratio: 4.93; 95% confidence interval [CI]:1.56 to 15.63 vs. 2.79; 95% CI: 1.12 to 6.97, respectively), and only the ICDSC significantly predicted hospital LOS with a mean of 17.59 additional days compared with the no-delirium group. Irrespective of delirium status, a sensitivity analysis of normal-to-increased arousal (RASS≥0) test results did not alter the predictive ability of ICDSC- or CAM-ICU-delirium for hospital mortality (adjusted odds ratio: 2.97; 95% CI: 1.06 to 8.37 vs. 3.82; 95% CI: 1.35 to 10.82, respectively). With reduced arousal (RASS<0), neither tool significantly predicted mortality or LOS. ConclusionsThe ICDSC identified more delirium cases and may have higher predictive validity for mortality and LOS than the CAM-ICU. However, arousal substantially affected performance. Future studies may want to consider patients’ arousal when deciding which tool to use to maximise the effects of delirium identification on patient mortality.