Background: Delirium is common in older hospitalized patients and is associated with poor outcomes, yet most cases go undetected. The best approach for systematic delirium identification outside the intensive care unit remains unknown.
Objective: To conduct a comparative effectiveness study of the Confusion Assessment Method for the ICU (CAM-ICU) and the newly developed 3-minute diagnostic assessment for delirium using the Confusion Assessment Method (3D-CAM) in general medicine inpatients.
Design: Cross-sectional comparative effectiveness study.
Setting: Two non-intensive care general medicine units at a single academic medical center.
Participants: Hospitalized general medicine patients aged ≥75 years.
Measurements: Clinicians performed a reference standard assessment for delirium that included patient interviews, family interviews, and review of the medical record. An expert panel determined the presence or absence of delirium using DSM-IV criteria. Two blinded research assistants administered the CAM-ICU and the 3D-CAM in random order, and we determined their diagnostic test characteristics compared to the reference standard.
Results: Among the 101 participants (mean age 84 ± 5.5 years, 61 % women, 25 % with dementia), 19 % were classified as delirious based on the reference standard. Evaluation times for the 3D-CAM and CAM-ICU were similar. The sensitivity [95 % confidence interval (CI)] of delirium detection for the 3D-CAM was 95 % [74 %, 100 %] and for the CAM-ICU was 53 % [29 %, 76 %], while specificity was >90 % for both instruments. Subgroup analyses showed that the CAM-ICU had sensitivity of 30 % in patients with mild delirium vs. 100 % for the 3D-CAM.
Conclusions: In this comparative effectiveness study, we found that the 3D-CAM had substantially higher sensitivity than the CAM-ICU in hospitalized older general medicine patients, and similar administration time. Therefore, the 3D-CAM may be a superior screening tool for delirium in this patient population.
Keywords: delirium; dementia; diagnosis; inpatient; screening.