Duchenne muscular dystrophy is an inherited disorder that involves muscle weakness, which quickly gets worse. Duchenne muscular dystrophy is a form of muscular dystrophy. It worsens quickly. Other muscular dystrophies (including Becker’s muscular dystrophy) get worse much more slowly. Duchenne muscular dystrophy is caused by a defective gene for dystrophin (a protein in the muscles). However, it often occurs in people without a known family history of the condition.Because of the way the disease is inherited, it usually affects boys. The sons of females who are carriers of the disease (women with a defective gene, but no symptoms themselves) each have a 50% chance of having the disease. The daughters each have a 50% chance of being carriers. Very rarely, a girl can be affected by the disease. Duchenne muscular dystrophy occurs in about 1 out of every 3,600 male infants. Because this is an inherited disorder, risks include a family history of Duchenne muscular dystrophy.Symptoms usually appear before age 6 and may appear as early as infancy. They include fatigue, learning difficulties (the IQ can be below 75) and intellectual disability (possible, but does not get worse over time).Muscle weakness a major characteristic of the disease, begins in the legs and pelvis, but also occurs less severely in the arms, neck, and other areas of the body. Other difficulties that arise are:problems with motor skills (running, hopping, jumping);frequent falls;trouble getting up from a lying position or climbing stairs;weakness quickly getting worse;progressive difficulty in walking; breathing difficulties and heart disease usually start by age 20.
Prednisone 0.75 mg/kg/d has significant benefit in Duchenne muscular dystrophy (DMD) management and should be considered the optimal prednisone dose. Prednisone 10 mg/kg/weekend is equally effective over a 12-month period, although long-term outcomes of this alternate regimen remain to be seen. Because of the expectation of significant adverse events (AEs) with corticosteroids, proper informed consent is required, and AEs should be discussed with patients and their families prior to therapy initiation and should be managed proactively. The American College of Rheumatology Task Force osteoporosis guideline recommends calcium and vitamin D supplementation for patients taking corticosteroids (any dose with an anticipated duration of ≥3 months) in order to maintain a total calcium intake of 1,200 mg/d and vitamin D intake of 800 IU/d through dietary sources and supplementation.
If a significant number of AEs develop, reducing the prednisone dose to 0.3 mg/kg/d may reduce the AE burden, albeit with less efficacy.
The AE profiles of deflazacort and prednisone vary slightly. Weight gain and cushingoid appearance may occur more frequently with prednisone than deflazacort, but cataracts are more frequently reported with deflazacort.
Prednisone, offered as an intervention for patients with DMD:
- Should be used to improve strength (Level B) and may be used to improve timed motor function (Level C)
- Should be used to improve pulmonary function (Level B)
- May be used to reduce the need for scoliosis surgery (Level C)
- May be used to delay the onset of cardiomyopathy by 18 years of age (Level C)
Deflazacort, offered as an intervention for patients with DMD, may be used to:
- Improve strength and timed motor function and delay the age at loss of ambulation by 1.4–2.5 years (Level C)
- Improve pulmonary function (Level C)
- Reduce the need for scoliosis surgery (Level C)
- Delay the onset of cardiomyopathy by 18 years of age (Level C)
- Increase survival at 5 and 15 years of follow-up (Level C)
Deflazacort and prednisone may be equivalent in improving motor function (Level C). There is insufficient evidence to establish a difference in effect on cardiac function (Level U). Prednisone may be associated with increased weight gain in the first years of treatment compared with deflazacort (Level C). Deflazacort may be associated with increased risk of cataracts compared with prednisone (Level C).
If patients with DMD are treated with prednisone, prednisone 0.75 mg/kg/d should be the preferred dosing regimen (Level B). Prednisone 10 mg/kg/weekend is equally effective over 12 months, but long-term outcome is not yet established. Prednisone 0.75 mg/kg/d is probably associated with significant risk of weight gain, hirsutism, and cushingoid appearance (Level B), with equal side effect profile seen over 12 months with the 10 mg/kg/weekend dosing.
Prednisone 0.3 mg/kg/d may be used as an alternative dosing regimen with lesser efficacy and fewer AEs (Level C). Prednisone 1.5 mg/kg/d is another alternative regimen; it may be equivalent to 0.75 mg/kg/d but may be associated with more AEs (Level C).
Data are insufficient to support or refute the following (all Level U):
- The addition of calcifediol and bisphosphonates (alendronate) as significant interventions for improving bone health in patients with DMD taking prednisone
- A benefit of bisphosphonates for improving survival in patients with DMD taking corticosteroids
- A benefit of prednisone for survival
- A significant difference in efficacy or AE rates among daily, alternate day, and intermittent regimens for prednisone or prednisolone dosing
- A preferred dose of deflazacort
- An effect of corticosteroids on quality of life (QoL)
Suggestions for Counseling
The following suggestions for counseling are the opinion of the authors and extend from logical conclusions of the recommendations.
Patients with DMD and their families should:
- Have a voice in the choice of the corticosteroid used, noting that the various corticosteroids differ in evidence supporting use, cost, availability, and AE profiles. When a corticosteroid has been agreed upon, a focused discussion of the risks particular to that corticosteroid should take place.
- Be informed of the risks and benefits of adding a bisphosphonate to corticosteroid treatment.
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