Validation of replacement questions for slowness and weakness to assess the Fried Phenotype: a cross-sectional study

When screening large populations, performance-based measures can be difficult to conduct because they are time consuming and costly, and require well-trained assessors. The aim of the present study is to validate a set of questions replacing the performance-based measures slowness and weakness as part of the Fried frailty phenotype (FRIED-P).

A cross-sectional study was conducted among community-dwelling older adults (≥ 60 years) in three Flemish municipalities. The Fried Phenotype (FRIED-P) was used to measure physical frailty. The two performance-based measures of the Fried Phenotype (slowness and weakness) were also measured by means of six substituting questions (FRIED-Q). These questions were validated through sensitivity, specificity, Cohen's kappa value, observed agreement, correlation analysis, and the area under the curve (AUC, ROC curve).

196 older adults participated. According to the FRIED-P, 19.5% of them were frail, 56.9% were pre-frail and 23.6% were non-frail. For slowness, the observed sensitivity was 47.0%, the specificity was 96.5% and the AUC was 0.717. For weakness, the sensitivity was 46.2%, the specificity was 83.7%, and the AUC was 0.649. The overall Spearman correlation between the FRIED-P and the FRIED-Q was r = 0.721 with an observed agreement of 76.6% (weighted linear kappa value = 0.663, quadratic kappa value = 0.738).

The concordance between the FRIED-P and FRIED-Q was substantial, characterized by a very high specificity, but a moderate sensitivity. This alternative operationalization of the Fried Phenotype-i.e., including six replacement questions instead of two performance-based tests-can be considered to apply as screening tool to screen physical frailty in large populations.