Danish version of the Tilburg Frailty Indicator - translation, cross-cultural adaption and validity pretest by cognitive interviewing

The Tilburg Frailty Indicator (TFI) is a self-administered questionnaire with a bio-psycho-social integrated approach that measures the degree of frailty in elderly persons. The TFI was developed in the Netherlands and tested in a population of elderly Dutch men and women. The aim of this study was to translate and culturally adapt the TFI to a Danish context, and to test face validity of the Danish version by cognitive interviewing. An internationally recognized procedure was applied as a basis for the translation process. The primary tasks were forward translation, reconciliation, back translation, harmonization and pretest. Pretest and review of the preliminary version by cognitive interviewing, were performed at a local community center and in an acute medical ward at the University Hospital in Aalborg, Denmark respectively. A large agreement regarding meaning of the items in the forward translation and reconciliation process was seen. Minor discrepancies were solved by consensus. Back translation revealed unclear wording in one matter. The harmonization committee agreed on a version for cognitive interviewing after revision of minor issues and thirty-four participants were interviewed. Two issues became evident and these were revised. The cognitive interviews and final lay-out resulted in minor adjustments as text type size, specific font, and lining for optimizing readability. In conclusion, we consider the TFI to be translated in such rigorous manner that the instrument can be further tested in clinical practice. The overall objective of the questionnaire being to identify frailty and improve the interventions relating to frail elderly persons in Denmark.