Validation of the revised 9-scale clinical frailty scale (CFS) in Greek language.

Among many screening tools that have been developed to detect frailty in older adults, Clinical Frailty Scale (CFS) is a valid, reliable and easy-to-use tool that has been translated in several languages. The aim of this study was to develop a valid and reliable version of the CFS to the Greek language. A Greek version was obtained by translation (English to Greek) and back translation (Greek to English). The “known-group” construct validity of the CFS was determined by using test for trends. Criterion concurrent validity was assessed by evaluating the extent that CFS relates to Barthel Index, using Pearson’s correlation coefficient. Both inter-rater and test–retest reliability were assessed using intraclass correlation coefficient. Known groups comparison supports the construct validity of the CFS. The strong negative correlation between CFS and Barthel Index (rs = − 0,725, p ≤ 0.001), supports the criterion concurrent validity of the instrument. The intraclass correlation was good for both inter-rater (0.87, 95%CI: 0.82–0.90) and test-retest reliability (0.89: 95%CI: 0.85–0.92). The Greek version of the CFS is a valid and reliable instrument for the identification of frailty in the Greek population.