Brazilian Portuguese version of the Clinical Frailty Scale Classification Tree and the Health Questionnaires: Validity and reliability study.

OBJECTIVES: Cross-culturally adapt the Clinical Frailty Scale (CFS) Classification Tree and CFS Health Questionnaires into Brazilian Portuguese and evaluate their validity and reliability. METHODS: Methodological study with elderly people, aged 60 or over, who attend community centers for daily activities. A cross-cultural adaptation of the CFS Classification Tree and CFS Health Questionnaires into Brazilian Portuguese was performed in accordance with recommended guidelines. The measurement properties of the final Brazilian version were evaluated. Criterion validity was assessed by comparing the CFS Classification Tree with the Edmonton Frail Scale, which was used as a reference instrument because it is a validated frailty measure based on the deficit accumulation model. Inter-rater reliability of questionnaires and the classification tree were tested using the first and second evaluators. Test-retest reliability was assessed (15-30 days apart) using data from the first evaluator (questionnaires) and a third evaluator (classification tree). RESULTS: The Brazilian Portuguese version of the CFS instruments was considered culturally and linguistically appropriate. Criterion validity demonstrated a strong correlation between the CFS Classification Tree and the Edmonton Frail Scale scores (Spearman's rho=0.70; p < 0.001) and an association between frailty classifications (p < 0.001, Cramer's V = 0.486, p < 0.001). Sensitivity and specificity were appropriate (0.72 and 0.70). Test-retest reliability (ICC=0.90 [95% CI 0.85-0.94]; p < 0.001) and inter-rater reliability (ICC=0.83 [95% CI 0.75-0.89]; p < 0.001) were considered high. CONCLUSIONS: The Brazilian version of the CFS Classification Tree and CFS Health Questionnaires demonstrate sufficient criterion validity and reliability for assessing frailty syndrome in older adults.