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

ABSTRACT 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