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, P<0.001) and short form method (ρ=0.66, P<0.001). Peak 3D-CAM-S raw scores also correlated with delirium duration and severity duration area under the curve measures (ρ=0.71, P<0.001 and ρ=0.91, P<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, P<0.001, n=177), slow-wave electroencephalogram power (ρ=0.3, P=0.001, n=73), and plasma neurofilament light (ρ=0.26, P<0.05, n=61) and tau (ρ=0.41, P<0.001, n=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.