Validation of the delirium diagnostic tool-provisional (DDT-Pro) in geriatric medical inpatients with diagnostic permutations of the 3Ds with and without delirium

Objective

Validations of brief delirium tools have not included analysis of psychiatric disorders comorbidities or control groups. We validated the Delirium Diagnostic Tool-Provisional (DDT-Pro) in 422 geriatric inpatients with high incidence of depression and/or dementia.

Methods

Cross-sectional study using two delirium reference standards, DSM-5-TR and Delirium Rating Scale-Revised-98 (DRS-R98). We assessed concurrent and construct DDT-Pro validity too.

Results

There were 117 (27.7%) delirium cases using DDT-Pro, 104 (24.6%) per DSM-5-TR and 93 (22.0%) per DRS-R98; 133 patients (31.5%) had depression and 105 (24.9%) dementia, some comorbid with delirium. DDT-Pro accuracy (AUC under ROC curve) ranges were 88.3–95.9% vs DSM-5-TR and 92.7–95.0% vs DRS-R98 for whole sample and four diagnostic groups, without statistical differences. DDT-Pro ≤6 had the most balanced sensitivity-specificity for delirium diagnosis against both DSM-5-TR and DRS-R98 with similar specificity but higher sensitivity for DRS-R98 than DSM-5-TR delirium, with the highest values in patients with depression and dementia (≥92% sensitivity, ≥81% specificity). Positive and negative likelihood ratios support diagnostic strength. Concurrent validity was high reflected by significant correlations (p < 0.001) of DDT-Pro total and item scores with DRS-R98 and Delirium Frontal Index scores, highest in groups with comorbid depression and/or dementia. The DDT-Pro represented a single construct for delirium demonstrated by one factor with high item loadings and high internal consistency reliability of its items.

Conclusions

The DDT-Pro demonstrated strong performance metrics in general hospital elderly inpatients with preexisting depression and/or dementia, which is unique among brief delirium tools. Its optimized cutoff score was the same as in other populations.