The Myotonic Dystrophy Health Index (MDHI) is a disease-specific patient-reported outcome measure. Here, the associations between the MDHI and other measures of disease burden in a cohort of 70 individuals with myotonic dystrophy type-1 (DM1) were measured. Participants completed assessments of strength, myotonia, motor and respiratory function, ambulation, and body composition. They also provided blood samples, underwent physician evaluations, and completed other patient-reported outcome measures. MDHI total and subscale scores were strongly associated with muscle strength, myotonia, motor function, and other clinical measures. 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.
