Interrater reliability and concurrent validity of 4AT for the detection of postoperative delirium: A prospective cohort study

Interrater reliability and concurrent validity of 4AT for the detection of postoperative delirium: A prospective cohort studyAbstract. Background: Numerous tools for detecting postoperative delirium are available. Guidelines recommend the 4 A's Test (4AT). However, there is little evidence on the validity and reliability of the German version of 4AT. Aim: To assess the interrater reliability of the German version of 4AT test for the detection of postoperative delirium in general surgical and orthopedic-traumatological patients, and the concurrent validity with the Delirium Observation Screening Scale (DOS). Methods: The present work is part of a prospective cohort study with a sample of 202 inpatients (=65 years) who underwent surgery. The interrater reliability of the 4AT (intraclass coefficients) was determined with a subsample of 33 subjects who were rated by two nurses. Concurrent validity between the DOS scale and the 4AT was calculated using Pearson's correlation coefficient. Results: Interrater reliability for the 4AT total score and dichotomized total score were 0.92 (95% CI 0.84-0.96) and 0.98 (95% CI 0.95-0.98), respectively. The correlation between DOS and 4AT (Pearson) was 0.54 (p < 0.001). Conclusions: The 4A test can be used by nurses as a screening instrument for the detection of postoperative delirium in older patients on general surgery and orthopedic traumatology wards. In case of positive 4AT results further assessment by nurse experts or physicians is required.