Association between dependence on activities of daily living and frailty in older people: a comparative study using the clinical-functional vulnerability index-20 and the frailty phenotype

• Frailty assessed by the CFVI-20 links more strongly to dependence compared to the FP. • The CFVI-20 is more accurate in identifying daily activities dependence than the FP. • The CFVI-20 should preferably be used to screen for frailty in primary care units. This study aimed to compare the strength of associations between dependence on basic activities of daily living (BADL) and instrumental activities of daily living (IADL) and frailty, assessed by the Clinical-Functional Vulnerability Index-20 (CFVI-20) and the Frailty Phenotype (FP). Additionally, it examined which instrument is more accurate in identifying older people with dependence. This cross-sectional study included a convenience sample of 185 community-dwelling older people. Dependence on BADL and IADL was assessed using the Katz and the Lawton and Brody scales, respectively. Frailty was evaluated using both the CFVI-20 and the FP. Logistic regression analyses were performed to investigate associations between frailty and dependence, and receiver operating characteristic curve analyses were used to evaluate the accuracy of both instruments in identifying dependence. Older people classified as at risk of frailty or frail by the CFVI-20 showed higher odds of dependence on both BADL and IADL compared to those classified as robust. According to the FP, older people classified as pre-frail or frail were more likely to be dependent on BADL, and frail participants were more likely to be dependent on IADL compared to older people classified as robust. The CFVI-20 demonstrated greater accuracy than the FP in identifying BADL dependence, whereas the accuracy of both instruments in identifying IADL dependence did not differ. Associations between frailty and dependence were stronger when frailty was assessed using the CFVI-20. This study contributes to the construct validity of the CFVI-20 and suggests its preferential use in primary care settings.