German translation, cross-cultural adaptation and diagnostic test accuracy of three frailty screening tools : PRISMA-7, FRAIL scale and Groningen Frailty Indicator

Abstract

Background: Routine screening for frailty could be used to timely identify older people with increased vulnerability und corresponding medical needs.

Objective: The aim of this study was the translation and cross-cultural adaptation of the PRISMA-7 questionnaire, the FRAIL scale and the Groningen Frailty Indicator (GFI) into the German language as well as a preliminary analysis of the diagnostic test accuracy of these instruments used to screen for frailty.

Methods: A diagnostic cross-sectional study was performed. The instrument translation into German followed a standardized process. Prefinal versions were clinically tested on older adults who gave structured in-depth feedback on the scales in order to compile a final revision of the German language scale versions. For the analysis of diagnostic test accuracy (criterion validity), PRISMA-7, FRAIL scale and GFI were considered the index tests. Two reference tests were applied to assess frailty, either based on Fried's model of a Physical Frailty Phenotype or on the model of deficit accumulation, expressed in a Frailty Index.

Results: Prefinal versions of the German translations of each instrument were produced and completed by 52 older participants (mean age: 73 ± 6 years). Some minor issues concerning comprehensibility and semantics of the scales were identified and resolved. Using the Physical Frailty Phenotype (frailty prevalence: 4%) criteria as a reference standard, the accuracy of the instruments was excellent (area under the curve AUC >0.90). Taking the Frailty Index (frailty prevalence: 23%) as the reference standard, the accuracy was good (AUC between 0.73 and 0.88).

Conclusion: German language versions of PRISMA-7, FRAIL scale and GFI have been established and preliminary results indicate sufficient diagnostic test accuracy that needs to be further established.

Keywords: Frail elderly; Outcome measure; Rehabilitation; Sensitivity and specificity.