Kihon Checklist to assess frailty in older adults: Some evidence on the internal consistency and validity of the Spanish version

Aim The aim of this study was to assess the internal consistency, hypothesis testing and criterion‐related validity of the Spanish versions of the Kihon Checklist (KCL) – the original 25‐item and reduced 15‐item versions – for screening frailty in community‐dwelling older adults. Methods A cross‐sectional study was carried out between March and September 2018 in Valencia province (Spain). A sample of 251 participants was recruited. Construct validity was assessed using four different frailty instruments, and alternative measures corresponding to the KCL domains (handgrip strength, gait speed, the Short Physical Performance Battery, skeletal muscle mass index, physical activity level, functional status, cognitive function, depressive mood, health‐related quality of life and nutritional status). Fried's Frailty Phenotype was used to evaluate criterion validity. Results Internal consistency assessed with Kuder–Richardson Formula had a value of 0.69 for the 25‐item version, slightly lower than the usual 0.7 for considering good reliability, and 0.71 for the 15‐item version. There were significant correlations between KCL versions and Fried's Frailty Phenotype, Edmonton Scale, Tilburg Indicator and FRAIL Scale. Consistent significant correlations were also obtained with all frailty measurements and instrumental activities of daily living, physical strength, eating, socialization, and mood domains of the KCL. The KCL closely correlated with other standardized measurements of physical function, cognitive function, depressive mood, and health‐related quality of life. The KCL also showed satisfactory diagnostic accuracy for frailty (area under the curve 0.891 for KCL‐25; area under the curve 0.857 for KCL‐15). The optimal cut‐off points were 5/6 and 3/4, respectively. Conclusions The findings suggest that both versions of the KCL, especially KCL‐15, showed adequate evidence of validity and internal consistency as a preliminary screening of frailty among community‐dwelling older adults in Spain. Geriatr Gerontol Int 2021; 21: 262–267.