Validation of the Modified Frailty Phenotype Measure in Older Mexican Americans

OBJECTIVES Develop and validate a modified frailty phenotype measure for older Mexican Americans participating in the Hispanic Established Populations for the Epidemiological Study of the Elderly (H-EPESE) and related studies. DESIGN Expert-based panel evaluation of content validity, cross-sectional analysis of construct validity, and longitudinal analysis of criterion validity for a modified version of the frailty phenotype measure. SETTING Five southwestern states. PARTICIPANTS A total of 1833 community-dwelling Mexican Americans aged 67 years or older. MEASUREMENTS Frailty was assessed using the frailty phenotype measure (weight loss, weakness, exhaustion, slowness, and low physical activity) and a modified frailty phenotype measure (replacing "low physical activity" with "limitations in walking half a mile"). Each individual was classified as non-frail, pre-frail, or frail based on both frailty measures (original vs modified). Expert panel consensus was used to examine content validity. Spearman correlation, kappa, weighted kappa, and bootstrapping kappa examined construct validity (n = 1833). Generalized linear mixed models, odds ratios, Cox proportional regression models, hazard ratios, and C statistics were used to analyze criterion validity (n = 1446) across four outcomes: hospitalization, physician visits, disability, and mortality from wave 3 (1998-99) through wave 8 (2012-13). RESULTS The original and modified frailty phenotype measures had a strong correlation (r = .89; P < .000) and agreement (kappa = .84; 95% confidence interval [CI] = .81-.86; weighted kappa = .86; 95% CI = .84-.88; bootstrap kappa = .84; 95% CI = .81-.86; bootstrap-weighted kappa = .86; 95% CI = .84-.88 with 1000 bootstrapping samples). Four outcome models showed similar risk predictions for both frailty measures, with the exception of physician visits for frail participants. CONCLUSION "Limitations in walking half a mile" can be used as a substitute criterion for "low physical activity" in assessing frailty. The modified frailty phenotype measure was comparable with the original frailty phenotype measure in H-EPESE participants over time. Our results indicate the modified frailty phenotype is a useful longitudinally frailty measure for community-dwelling older Mexican Americans.