Jeanne Dekdebrun

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

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

Myotonic dystrophy health index: Correlations with clinical tests and patient function

Introduction: The Myotonic Dystrophy Health Index (MDHI) is a disease‐specific patient‐reported outcome measure. Here, we examine the associations between the MDHI and other measures of disease burden in a cohort of individuals with myotonic dystrophy type‐1 (DM1). Methods: We conducted a cross‐sectional study of 70 patients with DM1. We examined the associations between MDHI total and subscale scores and scores from other clinical tests. Participants completed assessments of strength, myotonia, motor and respiratory function, ambulation, and body composition. Participants also provided blood samples, underwent physician evaluations, and completed other patient‐reported outcome measures. Results: MDHI total and subscale scores were strongly associated with muscle strength, myotonia, motor function, and other clinical measures. Conclusions: Patient‐reported health status, as measured by the MDHI, is associated with alternative measures of clinical health. These results support the use of the MDHI as a valid tool to measure disease burden in DM1 patients. Muscle Nerve, 2015 Muscle Nerve 53: 183–190, 2016