French translation and cross-cultural adaptation of The Myotonic Dystrophy Health Index.

INTRODUCTION: Validation studies of disease-specific instruments for myotonic dystrophy type-1 (DM1) are required prior to their global use in clinical trials involving different cultures and countries. Here we translate and culturally adapt the Myotonic Dystrophy Health Index (MDHI), a disease-specific patient-reported outcome (PRO) measure, for a French DM1 population.

METHODS: Using the International Society for Pharmacoeconomics and Outcomes Research Task Force method for translation and adaptation of PRO questionnaires, we created a French translation of the MDHI. We subsequently tested this instrument in a cohort of French-speaking patients with DM1.

RESULTS: The MDHI was forward and back translated and modified by consensus to create the most compatible translation. Cognitive interviews were conducted with 5 patients with DM1 to ensure the usability and understanding of the translation.

DISCUSSION: The French version of the MDHI is an optimal translation of the original instrument that is acceptable to native patients and ready for clinical trial use. Muscle Nerve 57: 686-689, 2018.