Risk Factors for First Fractures Among Males With Duchenne or Becker Muscular Dystrophy.
BACKGROUND
Fractures are a significant concern for individuals with Duchenne/Becker muscular dystrophy with 21% to 44% of males experiencing a fracture. Factors that increase or decrease the risk for fracture have been suggested in past research, although statistical risk has not been determined.


METHODS
In this retrospective cohort study, we used the Muscular Dystrophy Surveillance, Tracking and Research Network cohort, a large, population-based sample to identify risk factors associated with first fractures in patients with Duchenne or Becker muscular dystrophy. Our study cohort included males with Duchenne or Becker muscular dystrophy born between 1982 and 2006 who resided in Arizona, Colorado, Georgia, Iowa, and Western New York, retrospectively identified and followed through 2010. We utilized a multivariate Cox proportional hazard model to determine hazard ratios for relevant factors associated with first fracture risk including race/ethnicity, surveillance site, ambulation status, calcium/vitamin D use and duration, bisphosphonate use and duration, and corticosteroid use and duration.


RESULTS
Of 747 cases, 249 had at least 1 fracture (33.3%). Full-time wheelchair use increased the risk of first fracture by 75% for every 3 months of use (hazard ratio=1.75, 95% confidence interval, 1.14, 2.68), but corticosteroid use, bisphosphonate use, and calcium/vitamin D use did not significantly affect risk in the final adjusted model.


CONCLUSIONS
In this cohort, first fractures were common and full-time wheelchair use, but not corticosteroid use, was identified as a risk factor. The impact of prevention measures should be more thoroughly assessed.


CONCLUSIONS
Fractures are a significant concern for individuals with dystrophinopathies, but the contribution of various risk factors has not been consistently demonstrated.
*Department of Family Medicine, University of Colorado ¶Colorado Department of Public Health and Environment, Denver, CO †Department of Pediatrics, University of Arizona College of Medicine, Tucson, AZ ‡Seattle Children's Hospital, University of Washington School of Medicine, Seattle, WA §University of Iowa Carver College of Medicine, Iowa City, IA ∥Department of Neurology, School of Medicine and Dentistry, University of Rochester, Rochester, NY.
Katherine A
KA
James
Christopher
C
Cunniff
Susan D
SD
Apkon
Katherine
K
Mathews
Zhenqiang
Z
Lu
Caleb
C
Holtzer
Shree
S
Pandya
Emma
E
Ciafaloni
Lisa
L
Miller
D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D001130:Arizona; D002118:Calcium / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D003120:Colorado; D004164:Diphosphonates / Q000627:therapeutic use; D050723:Fractures, Bone / Q000453:epidemiology / Q000209:etiology*; D005845:Georgia; D006801:Humans; D015994:Incidence; D007484:Iowa; D008297:Male; D020388:Muscular Dystrophy, Duchenne / Q000150:complications*; D009518:New York; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014807:Vitamin D / Q000627:therapeutic use; D014910:Wheelchairs / Q000706:statistics & numerical data; D055815:Young Adult
D000305:Adrenal Cortex Hormones; D004164:Diphosphonates; D014807:Vitamin D; D002118:Calcium