Diagnostic accuracy of the Ottawa 3DY and Short Blessed Test to detect cognitive dysfunction in geriatric patients presenting to the emergency department

OBJECTIVES Cognitive dysfunction (CD) is a common finding in geriatric patients presenting to the emergency department (ED). Our primary objective was to determine the diagnostic accuracy of the Ottawa 3DY (O3DY) and Short Blessed Test (SBT) as screening tools for the detection of CD in the ED. Our secondary objective was to estimate the inter-rater reliability of these instruments. METHODS We conducted a prospective cross-sectional comparative study at an inner-city academic medical centre (annual ED visit census 86 000). Patients aged 75 years or greater were evaluated for inclusion, 163 were screened, 150 were deemed eligible and 117 were enrolled. The research team completed the O3DY, SBT and Mini-Mental State Exam (MMSE) for each participant. Descriptive statistics were calculated. Sensitivity and specificity of the O3DY and SBT were calculated in STATA V.11.2 using the MMSE as our criterion standard. RESULTS We enrolled 117 patients from June to November 2016. The median ED length of stay at the time of completion of all tests was 1:40 (IQR 1:34-1:46). The sensitivity of the O3DY was 71.4% (95% CI 47.8 to 95.1), and specificity was 56.3% (46.7-65.9). Sensitivity of the SBT was 85.7% (67.4-99.9) and specificity was 58.3% (48.7-67.8). The receiver operating characteristic area under the curve was calculated for the O3DY (0.51; 95% CI 0.42 to 0.61) and SBT (0.52; 95% CI 0.43 to 0.61) relative to the MMSE. Inter-rater reliability for the O3DY (k=0.64) and SBT (k=0.63) were good. CONCLUSION In a cohort of geriatric patients presenting to an inner-city academic ED, the O3DY and SBT tools demonstrate moderate sensitivity and specificity for the detection of CD. Inter-rater reliability for the O3DY and SBT were good. Future research on this topic should attempt to derive and validate ED-specific screening tools, which will hopefully result in more robust likelihood ratios for the screening of CD in ED geriatric patients.