Development of the AL-O-A Score for Delirium Screening in Acute Internal Medicine: a Monocentric Prospective Study

Abstract

Background Delirium occurs frequently in acute internal medicine wards and may worsen the patient’s prognosis; it deserves a fast, systematic screening tool. Objective Develop a delirium screening score for inpatients admitted to acute internal medicine wards. Design A monocentric prospective study between November 2019 and January 2020. Participants Two hundred and seventeen adult inpatients. Main Measures Within 48 h of hospital admission, physicians administered an index test to participants which explored potential predictors associated with the fluctuation of mental state, inattention, disorganised thinking and altered level of consciousness. On the same day, patients underwent a neuropsychological evaluation (reference standard) to assess for delirium. The score was constructed using a backward stepwise logistic regression strategy. Areas under the receiver operating curves (AUC) and calibration curves were drawn to calculate the score’s performance. The score was tested on subgroups determined by age, sex and cognitive status. Results The AL-O-A score (“abnormal or fluctuating ALertness, temporospatial Orientation and off-target Answers”) showed excellent apparent (AUC 0.95 (95% CI 0.91–0.99)) and optimism-corrected discrimination (AUC 0.92 (95% CI 0.89–0.96)). It performed equally well in subgroups with and without cognitive impairment (AUC 0.93 (95% CI 0.88–0.99) vs 0.92 (95% CI 0.80–0.99)); in men and women (AUC 0.96 (95% CI 0.94–0.99) vs 0.95 (95% CI 0.89–0.99)); and in patients younger and older than 75 years old (AUC 0.98 (95% CI 0.95–0.99) vs 0.93 (95% CI 0.87–0.99)). Conclusions A simple, 1-min screening test (AL-O-A score), even administered by an untrained professional, can identify delirium in internal medicine patients.