Aim Subsyndromal delirium is associated with prolonged intensive care unit stays, and prolonged mechanical ventilation requirements. The Prediction of Delirium for Intensive Care (PRE‐DELIRIC) model can predict delirium. This study was designed to verify if it can also predict development of subsyndromal delirium. Methods We undertook a single‐center, retrospective observation study in Japan. We diagnosed subsyndromal delirium based on the Intensive Care Delirium Screening Checklist. We calculated the sensitivity and specificity of the PRE‐DELIRIC model and obtained a diagnostic cut‐off value. Results We evaluated data from 70 patients admitted to the mixed medical intensive care unit of the Tokyo Medical University Hospital (Tokyo, Japan) between May 2015 and February 2017. The prevalence of subsyndromal delirium by Intensive Care Delirium Screening Checklist was 31.4%. The area under the receiver operating characteristic curve was 0.83 of the PRE‐DELIRIC model for subsyndromal delirium. The calculated cut‐off value was 36 points with a sensitivity of 94.3% and specificity of 57.1%. Subsyndromal delirium was associated with a higher incidence of delirium (odds ratio, 8.81; P
