Validity of cognitive function assessed by a subjective cognitive decline questionnaire as compared with objective cognitive tests in community‐dwelling older adults in China

Abstract

AbstractBackgroundSubjective cognitive decline (SCD) has been recognized as an early symptom of age‐related cognitive decline, but research on the validity of SCD questionnaire in the elderly population is limited. Thus, we aimed to evaluate the validity of a 7‐item SCD questionnaire in Chinese older adults.MethodThe study included 1585 participants (53.6% women; mean [SD] age: 78.7 [4.4] years) who completed the SCD questionnaire, Hasegawa Dementia Scale (HDS), and Mini‐Mental State Examination (MMSE) from the Rugao Longevity and Ageing Study (RuLAS) in 2019. MCI was defined according to established education‐specific cut‐off values of HDS and MMSE scores. We used sensitivity, specificity, Youden’s Index, and the receiver operating characteristic (ROC) curves to evaluate the discriminant ability of the SCD questionnaire. Spearman correlation coefficients were also used to measure the strength of correlation between SCD scores and objective cognitive function scores.ResultThe SCD score (range: 0‐7) with the cut‐off value of 4 displayed moderate‐to‐good sensitivity (Sen = 0.52) and specificity (Spec = 0.69), with Youden’s index of 0.21 and the area under the curve (AUC) of 0.62, in distinguishing cognitive impairment defined by objective cognitive tests. In addition, SCD scores have low‐to‐moderate correlations with overall scores of two cognitive tests (rHDS = ‐0.23; rMMSE = ‐0.28). Correlations between domain‐specific SCD and corresponding objective cognitive function scores ranged from ‐0.05 to ‐0.31.ConclusionOur study supported a reasonable discriminant ability of a 7‐item SCD questionnaire among Chinese older adults.