Validity and Reliability of the Memorial Delirium Assessment Scale-Thai Version (MDAS-T) for Assessment of Delirium in Palliative Care Patients

Abstract

Background: Delirium, a neuropsychiatric syndrome that occurs throughout medical illness trajectories, is frequently misdiagnosed. The Memorial Delirium Assessment Scale (MDAS) is a commonly used tool in palliative care (PC) settings. Our objective was to establish and validate the Memorial Delirium Assessment Scale-Thai version (MDAS-T) in PC patients.

Materials and methods: The MDAS was translated into Thai. Content validity, inter-rater reliability, and internal consistency were explored. The construct validity of the MDAS-T was analyzed using exploratory factor analysis. Instrument testing of the MDAS-T, the Thai version of the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU-T), and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition as the gold standard was performed. The receiver operating characteristic (ROC) curve was used to determine the optimal cutoff score. The duration of each assessment was recorded.

Results: The study enrolled 194 patients. The content validity index was 0.97. The intraclass correlation coefficient and Cronbach's α coefficient were 0.98 and 0.96, respectively. A principal component analysis indicated a homogeneous, one-factor structure. The area under the ROC curve was 0.96 (95% confidence interval [CI], 0.93-0.99). The best combination of sensitivity and specificity (95% CI) of the MDAS-T were 0.92 (0.85-0.96) and 0.90 (0.82-0.94), respectively, with a cutoff score of 9, whereas the CAM-ICU-T yielded 0.58 (0.48-0.67) and 0.98 (0.93-0.99), respectively. The median MDAS-T assessment time was 5 minutes.

Conclusion: This study established and validated the MDAS-T as a good and feasible tool for delirium screening and severity rating in PC settings.

Implications for practice: Delirium is prevalent in palliative care (PC) settings and causes distress to patients and families, thereby making delirium screening necessary. This study found that the MDAS-T is a highly objective and feasible test for delirium screening and severity monitoring in PC settings and can greatly improve the quality of care for this population.

Keywords: Delirium; MDAS; Palliative care; Screening; Sensitivity and specificity; Validity and reliability.

Figure 1

Receiver operating characteristic (ROC) curve and the area under the curve (AUC) for MDAS‐T, compared with delirium diagnosis by Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition diagnostic criteria. Abbreviation: CI, confidence interval.