title: Myotonic Dystrophy Health Index: initial evaluation of a disease-specific outcome measure.
abstract: BACKGROUND
  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.
authors.affiliation: The University of Rochester Medical Center, Department of Neurology, 601 Elmwood Avenue, Box 673, Rochester, New York, 14642, USA.
authors.forename: Chad
authors.initials: C
authors.lastname: Heatwole
authors.forename: Rita
authors.initials: R
authors.lastname: Bode
authors.forename: Nicholas
authors.initials: N
authors.lastname: Johnson
authors.forename: Jeanne
authors.initials: J
authors.lastname: Dekdebrun
authors.forename: Nuran
authors.initials: N
authors.lastname: Dilek
authors.forename: Mark
authors.initials: M
authors.lastname: Heatwole
authors.forename: James E
authors.initials: JE
authors.lastname: Hilbert
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Luebbe
authors.forename: William
authors.initials: W
authors.lastname: Martens
authors.forename: Michael P
authors.initials: MP
authors.lastname: Mcdermott
authors.forename: Nan
authors.initials: N
authors.lastname: Rothrock
authors.forename: Charles
authors.initials: C
authors.lastname: Thornton
authors.forename: Barbara G
authors.initials: BG
authors.lastname: Vickrey
authors.forename: David
authors.initials: D
authors.lastname: Victorson
authors.forename: Richard
authors.initials: R
authors.lastname: Moxley
mesh_terms: D000328:Adult; D000368:Aged; D017281:Cost of Illness; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000175:diagnosis*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D063868:Patient Outcome Assessment; D015203:Reproducibility of Results; D057566:Self Report / Q000592:standards; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires / Q000592:standards; D014481:United States
keywords: muscle disease; myotonic dystrophy type-1; patient-relevant; patient-reported outcome measure; therapeutic trial, quality of life