A Study of the Psychometric Properties of the "Stanford Proxy Test for Delirium": A New Screening Tool for the detection of Delirium

Abstract Background Delirium is a prevalent neuropsychiatric disorder associated with increased morbidity and mortality. Half of cases remain misdiagnosed. Objective Assess effectiveness of S-PTD in detecting delirium in inpatient setting. Design Method comparison study. Daily assessment with S-PTD, by patient’s nurse, and a neuropsychiatric assessment by a psychiatrist. Assessments were blinded. Participants Inclusion criteria: 18 years or older. Exclusion criteria: patient’s or surrogate’s unwillingness to participate, inability to consent if a surrogate was not available, and inability to communicate in English or Spanish. A total of 309 patients were approached: 27 declined participation, 4 were excluded, and 278 subjects were followed throughout hospital stay. In the end, 78 were excluded from lack of neuropsychiatric assessment, S-PTD, or both. One was excluded for lack of demographic data. Measurements Find sensitivity and specificity of the S-PTD in detecting delirium when compared to a neuropsychiatric assessment. Results Participants were on average 60.8 years old and 54.3% male. Patients who developed delirium were, on average, older (15.12 years, CI: 8.94 – 21.32). A total of 199 patients were analyzed; 43 patients (21.6%) met criteria for delirium. S-PTD detected 67 days with delirium (16.5%) of 405 hospital days, while neuropsychiatric evaluation identified 83 (20.5%). S-PTD has sensitivity of 80.72% and specificity of 90.37%. Conclusion S-PTD is an effective, comprehensive, and simple screening tool for delirium, that is robust against fluctuating symptoms and lack of cooperation. Use of S-PTD may enhance early diagnosis of delirium.