Japanese and French translation and linguistic validation of a patient-reported outcome tool to assess quality of life in patients with Immune Thrombocytopenia (ITP): the ITP Life Quality Index (ILQI)

Objectives: The Immune Thrombocytopenia (ITP) Life Quality Index (ILQI) is a 10-item patient-reported outcome (PRO) measure developed in US-English to assess health-related quality of life (HRQoL) of adults with ITP. Analysis of ILQI responses indicated differences between Western and non-Western countries. The objective of this study was to translate and linguistically validate the ILQI for Japan and France.

Methods: The ILQI underwent dual forwards/backwards translation with reconciliation and resolution. The translations were reviewed prior to conducting cognitive interviews with ITP patients (n = 5 Japan, n = 5 France). Analysis of interview transcripts highlighted required modifications to the ILQI translations. Japanese and French ITP experts reviewed the final translations for cultural relevance and appropriateness.

Results: Most of the Japanese and French forward/backwards translations were reconciled with no revision. The ILQI instructions and items were well understood by Japanese and French participants. Wording in one item of the Japanese version of the ILQI was revised to better align with the source instrument. Three terms/phrases in the French translation were revised due to misunderstanding, being deemed inaccurate or culturally inappropriate. Following review by ITP experts from Japan and France, minor modifications were made.

Conclusion: Findings confirm the linguistic validity of the ILQI in Japanese and French.