Association between Rapid Dementia Screening Test score and clinical events in elderly patients with cardiovascular disease: a retrospective cohort study

Cognitive decline is prevalent among patients with cardiovascular disease (CVD). Cognitive measurement has been considered as a standard assessment for secondary prevention; however, standard cognitive tests are sometimes infeasible due to time constraints. This study aimed to examine the association between the Rapid Dementia Screening Test (RDST), a brief screening tool for cognitive function, and clinical events in elderly patients with CVD. This retrospective cohort study included 140 hospitalized patients with CVD who participated in inpatient cardiac rehabilitation (median age, 75 years; male, 67%). Cognitive function for each patient was assessed using the RDST and Montreal Cognitive Assessment (MoCA), a standard test of mild cognitive impairment. The clinical events assessed as outcomes included all-cause mortality and unplanned rehospitalization. Receiver-operating characteristic (ROC) curve analysis showed similar predictive accuracy for the study outcome (P = 0.337) between the RDST [area under the curve, 0.651; 95% confidence interval (CI), 0.559-0.743] and MoCA (0.625; 0.530-0.720). The ROC analysis identified a cut-off value of 9 points for the RDST (sensitivity, 77.8%; specificity, 50.5%). Patients with RDST ≤9 showed a poor survival rate compared with those with ≥10 points (log-rank test, P = 0.002; hazard ratio, 2.94, 95% CI, 1.46-5.94). This result was consistent even after adjusting for potential confounders. The RDST was associated with clinical events in elderly patients with CVD and its predictive capability was comparable with that of MoCA, a standard cognitive test. The RDST may be useful in CVD as an alternative screening tool for cognitive decline.