Measuring Frailty in Older Canadians: An Analysis of the Canadian Longitudinal Study on Aging

Abstract

Introduction: Frailty is characterized by vulnerability to declining health and increased risk for adverse health outcomes. Measuring frailty would be beneficial for developing interventions and assessing healthcare resource needs. No standardized measurement tool for frailty has been established. The objective of this thesis was to evaluate the frailty of participants in the Canadian Longitudinal Study on Aging (CLSA). Methods: A Frailty Index (FI) was constructed for CLSA participants based on the cumulative deficit theory of frailty. Exploratory factor analysis was conducted to study the underlying constructs of frailty and identify key factors. A hypothesized measurement model for frailty was specified. The model was modified and tested using structural equation modelling (SEM) to improve goodness-of-fit. A new frailty measurement tool was created and the construct validity of the new tool and the Frailty Index were evaluated. Results: A FI was calculated for 20,874 CLSA participants (Mean 0.14 SD 0.07). The maximum FI value was 0.68. A model containing all hypothesized variables had good fit of the data, and all variables contributed significantly. A simplified model also showed good fit and included four domains: upper-body strength, lower-body strength, dexterity, and depressive symptoms. These results persisted in an independent dataset. A Simplified Frailty (SF) score was created based on this simplified model. The FI and SF scores showed significant agreement and associations with sociodemographic variables were as predicted. Conclusions: A FI was simple to construct in the CLSA, having good fit of the data and construct validity. These results are consistent with previous research on the cumulative deficit theory of frailty. A simplified frailty model revealed key domains of frailty and resulted in a potentially useful short screening tool. The FI is recommended as a valid and reproducible approach for measuring frailty in the CLSA and similar population datasets.