RESUMO
BACKGROUND: Delirium is one of the most common adverse events in older people during hospitalization, especially in the emergency department. Reliable, easy-to-use instruments are necessary to properly manage delirium in this setting. This study aims to evaluate the diagnostic validity of the Spanish version of the 4 'A's Test (4AT) in the ED. METHODS: A diagnostic accuracy study was conducted in patients over 65 years old admitted to the Emergency Department who did not have a formal diagnosis of dementia or a severe mental health disorder. Face and content validity were evaluated by an expert panel. Emergency nurses performed the evaluation with 4AT, whilst blinded and trained researchers assessed patients with the Revised Delirium Rating Scale as the gold standard. The content validity index, sensitivity, specificity, positive and negative predictive values, likelihood ratios, Youden's Index and ROC curves were calculated to evaluate the diagnostic accuracy of the instrument. RESULTS: Of 393 eligible patients, 380 were finally analyzed. Content validity yielded a median content validity index of 4 (interquartile range: 0). The Spanish 4AT sensitivity (95.83%; 95% ECI: 78.9-99.9%), specificity (92.98%; 95% CI: 89.8-95.4%), positive predictive value (47.92%) and negative predictive value (99.7%) were satisfactory. Youden's index was 0.89. Positive likelihood ratio was 13.65, and negative likelihood ratio 0.045. The area under the curve was 0.97. CONCLUSIONS: The Spanish version of the 4AT for use in the Emergency Departments is easy-to-use and applicable. The validation results indicate that it is a valid instrument with sufficient predictive validity to identify patients at risk of delirium in the Emergency Departments. Moreover, it is a tool that facilitates the management of an adverse event that is associated with increased mortality and morbidity.