The 3-Minute Diagnostic Confusion Assessment Method severity score correlates with the Delirium Rating Scale-Revised-98 and with biomarkers of delirium.

Background: Several methods are used to measure delirium severity in the postoperative period. Here, we compare severity scores from two common assessment methods: the 3-Minute Diagnostic Confusion Assessment Method (3D-CAM) and the Delirium Rating Scale-Revised-98 (DRS).

Methods: Data were collected as part of an ongoing observational cohort study of perioperative delirium in patients >65 yr old undergoing major elective surgery with an anticipated hospital stay of at least 2 days. Patients were excluded if they had a documented history of dementia, resided in a nursing home, underwent neurosurgery, or could not complete neurocognitive testing. Patients underwent paired 3D-CAM and DRS assessments before and after operation along with EEG, cognitive testing, and plasma biomarker analysis.

Results: Of 226 subjects enrolled, 204 completed both the 3D-CAM and DRS assessments. Peak 3D-CAM severity (3D-CAM-S) scores correlated with peak DRS severity scores, for both the raw (ρ=0.74, <0.001) and short form method (ρ=0.66, <0.001). Peak 3D-CAM-S raw scores also correlated with delirium duration and severity duration area under the curve measures (ρ=0.71, <0.001 and ρ=0.91, <0.001, respectively). Similar to prior reports with the DRS, 3D-CAM-S raw scores correlated with worse performance on the Trail Making Test B (ρ=0.37, <0.001, =177), slow-wave electroencephalogram power (ρ=0.3, =0.001, =73), and plasma neurofilament light (ρ=0.26, <0.05, =61) and tau (ρ=0.41, <0.001, =63).

Conclusions: The 3D-CAM-S severity scores correlated with DRS, delirium duration, and biomarkers of delirium. The 3D-CAM, which is easier to implement than the DRS in postoperative patients, may provide a comparable assessment of delirium severity in this population.

Clinical Trial Registration: NCT03124303.