Development and validation of the Informant Assessment of Geriatric Delirium Scale (I-AGeD). Recognition of delirium in geriatric patients.

Abstract

Delirium is common in older patients admitted to hospital. Information obtained from patient's relatives or caregivers may contribute to improved detection. Our aim was to develop a caregiver based questionnaire, the Informant Assessment of Geriatric Delirium (I-AGeD), to assist in better recognition of delirium in elderly patients. A cross-sectional observational study using a scale construction patient cohort and two validation cohorts was conducted at geriatric departments of two teaching hospitals in The Netherlands. Delirium status, based on DSM-IV criteria, was assessed directly on admission by a geriatric resident and evaluated within the first 48 h of admission. Caregivers filled out a 37-item questionnaire of which 10 items were selected reflecting delirium symptoms, based on their discriminatory abilities, internal consistency and inter-item correlations. A total of 88 patients with complete study protocols in the construction cohort were included. Average age was 86.4 (SD 8.5), and 31/88 patients had delirium on admission. Internal consistency of the 10-item I-AGeD was high (Cronbach's alpha = 0.85). At a cut-off score of >4 sensitivity was 77.4% and specificity 63.2%. In patients without dementia, sensitivity was 100% and specificity 65.2%. Validation occurred by means of two validation cohorts, one consisted of 59 patients and the other of 33 patients. Sensitivity and specificity in these samples ranged from 70.0% to 88.9% and 66.7% to 100%, respectively. The newly constructed caregiver based I-AGeD questionnaire is a valid screening instrument for delirium on admission to hospital in geriatric patients.