Abstract
<title>Abstract</title> <p>Background Postoperative delirium (POD) is a common and clinically important complication in older adults. However, its timely detection in routine postoperative care remains challenging. The Family Confusion Assessment Method (FAM-CAM) is a caregiver-administered instrument designed to identify the symptoms of delirium via family observation. The current study aimed to translate the FAM-CAM into Thai (Thai FAM-CAM), culturally adapt it, and evaluate its criterion validity for detecting POD in older surgical patients. Methods This prospective methodological validation study was conducted in two phases. In phase 1, the original English version of the FAM-CAM was translated and culturally adapted into Thai using forward translation, synthesis, back-translation, and expert review. Content validity was assessed using the Index of Item-Objective Congruence (IOC). In phase 2, criterion validation was performed on 100 patient–caregiver dyads involving surgical patients aged ≥ 65 years. The caregivers completed the Thai FAM-CAM questionnaire after patient surgery. A trained investigator who was blinded to caregiver ratings assessed each patient using the CAM as the reference standard. Diagnostic performance was evaluated using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and the area under the receiver operating characteristic curve (AUC). Results The Thai FAM-CAM had an excellent content validity, with an overall IOC of 0.97. In total, 9 (9.00%) of 100 patients were diagnosed with POD using CAM. Compared with patients without delirium, those with POD were more likely to be male and have chronic obstructive pulmonary disease, a poorer functional status, lower Mini-Cog and modified Barthel Index scores, higher Charlson Comorbidity Index scores, longer surgical durations, and a greater blood loss volume. The Thai FAM-CAM had an excellent diagnostic performance, with an AUC of 0.995, sensitivity of 100.00%, specificity of 98.91%, PPV of 90.00%, NPV of 100.00%, and accuracy of 99.00%. Conclusions The Thai FAM-CAM is a valid and highly accurate caregiver-administered instrument for screening POD in older surgical patients. It may be a practical adjunct to perioperative delirium surveillance and support family involvement in the early identification of delirium in older adults.</p>