Usefulness of the Japanese version of Rapid Dementia Screening Test for mild cognitive impairment in older patients with cardiovascular disease: a cross-sectional study

BACKGROUND: Cognitive decline is common among older patients with cardiovascular disease (CVD) and can decrease their self-management abilities. However, the instruments for identifying mild cognitive impairment (MCI) are not always feasible in clinical practice. Therefore, this study evaluated whether MCI could be detected using the Japanese version of the Rapid Dementia Screening Test (RDST-J), which is a simple screening tool for identifying cognitive decline. METHODS: This retrospective single-center study included patients who were ≥ 65 years old and hospitalized because of CVD. Patients with a pre-hospitalization diagnosis of dementia were excluded. Each patient’s cognitive function had been measured at discharge using the RDST-J and the Japanese version of the Montreal Cognitive Assessment (MoCA-J), which is a standard tool for MCI screening. The correlation between the two scores was evaluated using Spearman’s rank correlation coefficient. Receiver operating characteristic (ROC) analysis was also to evaluate whether the RDST-J could identify MCI, which was defined as a MoCA-J score of ≤ 25 points. RESULTS: The study included 78 patients (mean age: 77.2 ± 8.9 years). The RDST-J and MoCA-J scores were strongly correlated (r = 0.835, P < 0.001). The ROC analysis revealed that an RDST-J score of ≤ 9 points provided 75.4% sensitivity and 95.2% specificity for identifying MCI, with an area under the curve of 0.899 (95% CI: 0.835−0.964). The same cut-off value was identified when excluding patients with a high probability of dementia (RDST-J score of ≤ 4 points). CONCLUSIONS: The RDST-J may be a simple and effective tool for identifying MCI in older patients with CVD.