Validation of the R₂CHADS₂ and CHADS₂ Scores for Predicting Post-stroke Cognitive Impairment

Objective Post-stroke cognitive impairment often afflicts stroke survivors and is a major obstacle both for cognitive and physical rehabilitation. Stroke risk scores ["Congestive heart failure, Hypertension, Age ≥75 years, Diabetes mellitus, Stroke" (CHADS₂) and "CHADS₂ + creatinine clearance <60 mL/min" (R₂CHADS₂)] are used to assess the future risk of cardioembolic stroke in patients with atrial fibrillation (AF). However, congestive heart failure, hypertension, aging, diabetes mellitus, stroke, and renal dysfunction are also risk factors for cognitive impairment. Methods Sixty-two patients with nonvalvular AF-induced cardioembolic stroke underwent cognitive testing, including the Japanese version of the Montreal Cognitive Assessment (MoCA-J), Mini-Mental State Examination (MMSE), and Apathy Scale. The correlations between the MoCA-J/MMSE/Apathy Scale scores and stroke risk scores were examined. Results The average CHADS₂ and R₂CHADS₂ scores were 4.1±1.0 and 5.6±1.6, respectively. The average MoCA-J, MMSE, and Apathy Scale scores were 17.4±6.2, 22.0±5.3, and 20.0±8.9, respectively. The CHADS₂ and R₂CHADS₂ scores were negatively correlated with the MoCA-J/MMSE and positively correlated with the Apathy Scale. The R₂CHADS₂ score was more sensitive to poststroke cognitive impairment than the CHADS₂ score. This correlation was stronger for MoCA-J than for MMSE, as the MMSE scores were skewed toward the higher end of the range. The results for individual MoCA-J and MMSE subtests indicated that the visuoexecutive, calculation, abstraction, and remote recall functions were significantly decreased after cardioembolic stroke. Conclusion These results suggest that the R₂CHADS₂ and CHADS₂ scores are useful for predicting post-stroke cognitive impairment.