Chen S, Honda T, Chen T, et al.

BMC Geriatr 2015;15:36

Publication date: April 2, 2015


The increasing incidence and prevalence of frailty due to population aging poses a great challenge to public healthcare and social care systems as demands for medical and care resources increase. Early screening for frailty in routine clinical practice, especially in primary care settings, is of great significance considering its high prevalence, reversibility, and prognostic value.

Two main operational definitions of frailty that receive broad acceptance are the frailty phenotype proposed and validated by Fried et al. the Cardiovascular Health Study (CHS) and the Frailty Index proposed and validated by Rockwood et al. in the Canadian Study of Health and Aging. The CHS frailty phenotype defines the presence of frailty and pre-frailty using five core components of the frailty cycle. However, the measurement of the low physical activity domain has not been standardized, which to some extent hinders the widespread application of the frailty phenotype in primary care practice.

The main objective of this study reported by Chen et al. was to define the low physical activity domain of the frailty phenotype using accelerometer-based measurement and to evaluate the internal construct validity among older community-dwellers. The authors conducted a cross-sectional study of 1,527 community-dwelling older men and women aged 65 and over enrolled in the Sasaguri Genkimon Study, a cohort study carried out in a west Japanese suburban community.

Frailty phenotypes were defined by the following five components: unintentional weight loss, low grip strength, exhaustion, slow gait speed, and low physical activity. Physical activity was objectively measured with a tri-axial accelerometer. A latent class analysis (LCA) was performed to assess whether the five components could aggregate statistically into a syndrome.

The estimated prevalence of frailty was 9.3% and 43.9% of the participants were identified as pre-frail. The percentage of low physical activity was 19.5%. Objectively-assessed physical activity and other components aggregated statistically into a syndrome. Increased age, poorer self-perceived health, depressive and anxiety symptoms, not consuming alcohol, no engagement in social activities, and cognitive impairment were associated with increased odds of frailty status, independent of co-morbidities.

This study represents the first attempt using a tri-axial accelerometer to define energy expenditure of physical activity for the frailty phenotype. The results confirm that the five components of the frailty phenotype can statistically aggregate into a syndrome, providing evidence for the internal construct validity of our measures. Objective measurement may potentially standardize the low physical activity component and improve diagnostic accuracy of the frailty phenotype.


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