Get access

Myotonic Dystrophy Health Index: Initial evaluation of a disease-specific outcome measure


  • Partial support for this research was provided by the National Institute of Arthritis and Musculoskeletal and Skin Disorders (1K23AR055947), the Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center (NINDS U54NS48843), the Muscular Dystrophy Association, and the Saunders Family Fund. The project described in this publication was also supported by the University of Rochester CTSA award number UL1 RR024160 from the National Center for Research Resources and the National Center for Advancing Translational Sciences of the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Additional information regarding the MDHI is available at the Neuromuscular Institute of Quality-of-Life Studies and Outcome Measure Development website and MDHI licensing opportunities can be reviewed at:


Introduction: In preparation for clinical trials we examine the validity, reliability, and patient understanding of the Myotonic Dystrophy Health Index (MDHI). Methods: Initially we partnered with 278 myotonic dystrophy type-1 (DM1) patients and identified the most relevant questions for the MDHI. Next, we used factor analysis, patient interviews, and test–retest reliability assessments to refine and evaluate the instrument. Lastly, we determined the capability of the MDHI to differentiate between known groups of DM1 participants. Results: Questions in the final MDHI represent 17 areas of DM1 health. The internal consistency was acceptable in all subscales. The MDHI had a high test–retest reliability (ICC = 0.95) and differentiated between DM1 patient groups with different disease severities. Conclusions: Initial evaluation of the MDHI provides evidence that it is valid and reliable as an outcome measure for assessing patient-reported health. These results suggest that important aspects of DM1 health may be measured effectively using the MDHI. Muscle Nerve 49: 906–914, 2014