Content verification of the EORTC QLQ-C30/EORTC QLQ-BR23 with the International Classification of Functioning, Disability and Health.

Purpose: The aims of this study were to estimate the extent to which the content of the EORTC QLQ-C30 and EORTC QLQ-BR23 goes beyond functioning and include global feeling of well-being.

Methods: Respectively, 21 and 13 healthcare professionals agreed to link the EORTC QLQ-C30 and EORTC QLQ-BR23 to the ICF. Mappers were asked to independently identify appropriate codes for the corresponding items of the EORTC QLQ-C30 and EORTC QLQ-BR23 following standardized linking rules and methodology. A Delphi technique was used in order to reach consensus. The threshold of agreement was 70 %. Rounds were stopped when the threshold was obtained or when it was clear that no consensus would be reached.

Results: A total of 25 items out of 30 were endorsed for the EORTC QLQ-C30: 8 items were endorsed at the 4-digit level, 15 items at the 3-digit level, and 2 items reach the consensus that the items were not cover within the ICF. Only 2 items out of 23 did not reach consensus in the EORTC QLQ-BR23. Of the 21 items endorsed, 3 items were endorsed at the 5-digit level, 10 items at the 4-digit level, and 8 at the 3-digit level.

Conclusion: This study demonstrates that the content of the EORTC QLQ-C30 goes beyond functioning and includes global feeling of well-being and that the content of the EORTC QLQ-BR23 is related to functioning. Furthermore, linking items to the ICF framework could be an additional method to validate the content of health-related questionnaires.