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Three Part Question

In [children with Duchenne muscular dystrophy]do [glucocorticoid corticosteroids] [prolong ambulation, improve muscle function and reduce complications]?

Clinical Scenario

A 3-year-old boy was seen in the community paediatric clinic for follow up of his Duchenne muscular dystrophy (DMD). There have been recent discussions about starting him on steroids. His parents would like to know if treatment with glucocorticoid corticosteroids (GCs) has been shown to prolong ambulation and the best age to start steroids. They also want to know if steroids reduce the complications of DMD and if the side effects of long-term steroids are acceptable.

Search Strategy

Secondary sources
A search of The Cochrane Library yielded one relevant review.

Primary sources
Advanced searches of MEDLINE and EMBASE were carried out.
Search terms were Duchenne muscular dystrophy, muscular dystrophy, Duchenne, steroids, corticosteroids, glucocorticoids.

Search Outcome

A total of 249 studies were identified and abstracts were screened for relevance. Further assessment of the 50 relevant articles found yielded five studies which are discussed below

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Manzur et al 2008	(reviewing data from four double-blind RCTs by Angelini, Griggs, Mendell et al and Rahman, and a randomised, placebo controlled, crossover trial by Beenakker et al) 249 DMD children Corticosteroids (n=161), controls (n=88) 216 Participants ambulatory Prednisone (n=134), prednisolone (n=10) and DFZ (n=17) Four studies: prednisone daily for 6 months Angelini: DFZ 2 mg/per kg on alternate days	Meta-analysis of five randomised control trails	1. Primary outcome: prolongation of ambulation 2. Strength outcome measures: (a) manual muscle strength testing: MRC strength scores or hand held dynamometry; (b) functional outcome measures: Motor Ability Score, Functional Score 3. Adverse events	1. Prolongation of ambulation: prolonged by 13 m in those who became wheelchair bound (54% of controls vs 23% of DFZ group) 2. Muscle strength: (a) statistically significant improvement in functional parameters; (b) after 2 years, significant change in MRC index including higher score for walking, chair rising (p<0.02) and time of Gower's manoeuvre (p<0.05)	4/17 (DFZ) became “wheelchair bound” at a mean age of 33.2 months vs 20.5 months in 6/11 (controls). The difference of 13 months was reported as “mean prolongation of walking”. But 13 (DFZ) and 5 (controls) still walking at the end of the study were not included The majority of the studies were short term (6 months), the longest being of 2 years’ duration. Chronic use side effects, such as reduced bone mineral density, fracture, cataracts and growth failure, will not be evident from short-term studies
Praden 2006	67 DMD patients Prednisolone (n=44), controls (n=23) Patients with clinically worsening muscle function.Prednisolone (0.75 mg/kg/day); both groups received vitamin E	Open controlled trial	Fall frequency, limb muscle power, ability to lift weights, Gower's manoeuvre, walking 9 m and climbing 13 stair steps	All parameters stable for 1 year. At 2 years, deterioration less than natural course of events Wheelchair bound by a mean age of 169±9 (treatment group) and 132±8 months (controls)	Adverse effects in 24: 14 (obesity), 3 (measles), 4 (pulmonary TB), 2 (recurrent infection) and 1 due to high WCC. Stopped in 5 as no improvement in power
Biggar 2006	74 boys with DMD (aged 10–18 years) (1990–2004) DFZ started at clinical evidence of worsening muscle function. DFZ (n=40) and controls (n=34)	RCT	Muscle strength: rise from supine to standing, climbing stairs, walking 10 m without aids	Walking (10 m): 81% at 12 years, 76% at 15 years, 33% walked independently at 18 years. All controls stopped walking by 12 years (mean 9.8±1.8) Scoliosis: at 18 years, 90% of controls and 10% of DFZ group had spinal curvature of >20° Cardio-respiratory: 47% of controls received nocturnal ventilation, none in the DFZ group. 54% of controls and 10% of the DFZ group had cardiac (LV) dysfunction. Seven controls lost >25% body weight and four required NG feeds but none of DFZ group did so.	35% of controls died at a mean age (SD) of 17.6±1.7 years of cardiorespiratory complications. Two of DFZ group died (at 13 and 18 years) from cardiac failure. DFZ group: significantly shorter, no excessive weight gain, asymptomatic cataracts (55%). DFZ has significant impact on health, quality of life and health care costs for boys with DMD, but few side effects
Ricotti et al 2011	Multicentre study of 428 ambulant boys with DMD (2003–2011. Daily prednisolone (DP=136), prednisolone 10 days on/10 days off (IP=154), alternate day prednisolone (AD=15), DFZ (n=19)	Cohort study	Loss of ambulation, timed 10 min run, time rising from floor, side-effects	Loss of ambulation 27% (IP) vs 22% (DP) Median age: 12 years (IP), 14 (DP). Above 7 years of age, IP group 5% were slower at timed 10 min run; 6% were slower in floor rising time	DP group had less disability progression especially over 7 years of age. Steroid related side effects: Cushingoid features, GI symptoms, hypertension, vertebral and long bone fractures, and behavioural changes
Parreira et al 2010	90 children with DMD (aged 5–12 years) on GCs for 1–7 years on prednisolone	Prospective cohort (level 2b)	Muscle strength, function: Hammersmith motor ability score, MRC score by same physiotherapist	Hammersmith score: decrease of 0.76 per year Relationship between MRC scale and patient age: decrease of 3.65 points (on Scott's study)	Comparison with previously established data

Comment(s)

DMD is the most common muscular dystrophy of childhood with an incidence of 1 in 3500 male live births. Children are usually diagnosed around 5 years of age and develop progressive muscle degeneration leading to loss of independent ambulation by 13 years of age. These patients are mostly wheelchair bound by their teens and respiratory, orthopaedic and cardiac complications develop. The mean age of death used to be around 19 years (Dubowitz, 1995; Emery, 2003). References: The Muscular Dystrophy Campaign states that “with high standards of medical care young men with Duchenne muscular dystrophy are often living well into their 30s”. The Cochrane review has shown that GCs improved muscle strength and function over 6 months. Improvements were seen in functional parameters including time taken to rise from the floor (Gower's manoeuvre), 9 m walking time, four-stair climbing time, ability to lift weights, leg function grade and forced vital capacity.1 Loss of walking ability at a mean age of 9.5 years (range 6–13 years) is followed by the development of scoliosis, which can be progressive during the pubertal growth spurt years. Data from non-randomised studies suggest that prolongation of ambulation reduces the risk of the development and progression of scoliosis (Tunca, 2001; Yilmaz, 2004). Kinali et al have studied the impact of intermittent low dose steroids in children under 5 years of age and found a striking response that suggested that there may be an optimal window for the treatment of DMD in the early stages of the disease, and reported that an intermittent, low-dosage prednisolone regime is well tolerated and can be safely given long-term in young children with DMD. In the UK NorthStar Clinical Network study, boys on daily prednisolone had less disability progression compared with other regimens but had more steroid related side effects. The Beenakker study found that although adverse effects were present, patient quality of life was not affected by prednisolone. There is evidence from randomised controlled trials to show that treatment with GCs in DMD improves muscle strength and function for 6 months to 2 years, and respiratory muscle strength and function for 6 months. The most effective prednisolone regime is probably 0.75 mg/kg daily. There is consensus that steroids may be started at the plateau stage prior to loss of ambulation. The long-term benefits and harms are not clear, but studies suggest that the beneficial effects on ambulation may be associated with significant steroid related adverse events.

Editor Comment

DFZ, deflazacort; DMD, Duchenne muscular dystrophy; GCs, glucocorticoid corticosteroids; GI, gastrointestinal; LV, left ventricular; MRC, Medical Research Council; NG, nasogastric; RCT, randomised controlled trial; TB, tuberculosis.

Clinical Bottom Line

Glucocorticoid corticosteroids in Duchenne muscular dystrophy (DMD) improve muscle strength and function for 6 months to 2 years. (Grade A) In children with DMD, treatment with the steroid deflazacort has been shown to improve pulmonary and cardiac function and such children required less medical intervention. (Grade B) Steroids may be started at the plateau stage prior to loss of ambulation. (Grade C)

References

1. Manzur AY, Kunter T, Pike M, et al. Glucocorticoid corticosteroids for duchenne muscular dystrophy. Cochrane Database Syst Rev 2008;1:CD003725 G
2. Angelini C. Deflazacort in Duchenne dystrophy: study of long-term effect. Muscle Nerve 1994;17:386–9
3. Griggs RC. Prednisone in Duchenne dystrophy. A randomized controlled trial defining the course and dose response. Clinical Investigation of Duchenne Dystrophy Group. Arch Neurol 1991;48:383–8.
4. Mendell JR, Moxley RT, Griggs RC, et al. Randomized, double-blind six-month trial of prednisone in Duchenne's muscular dystrophy. N Engl J Med 1989;320:1592–7.
5. Rahman MM. Prednisolone in Duchenne muscular dystrophy. Bangladesh Med Res Counc Bull 2001;27:38–42
6. Beenakker EA, Fock JM, Van Tol, et al. Intermittent prednisone therapy in Duchenne muscular dystrophy. A randomized controlled trial. Arch Neurol 2005;62:128–32.
7. Pradhan S. Prednisolone in Duchenne muscular dystrophy with imminent loss of ambulation. J Neurol 2006;253:1309–16.
8. Biggar WD. Long-term benefits of deflazacort treatment for boys with Duchenne muscular dystrophy in their second decade. Neuromuscul Disord 2006;16:249–55.
9. Ricotti V, Ridout D, Scott E, et al. On behalf of UK NorthStar Clinical Network. World Muscle Soc Congress 2011.
10. Kinali M, Mercuri E, Main M, et al. An effective, low-dosage, intermittent schedule of prednisolone in the long-term treatment of early cases of Duchenne dystrophy. Neuromuscul Disord 2002;12(Suppl 1) S169–74.
11. Bushby. Diagnosis and management of Duchenne muscular dystrophy, part 1 : diagnosis, and pharmacological and psychosocial management. Lancet Neurol 2010;9:77–93.
12. Dubowitz V. The muscular dystrophies. In: Dubowitz V, ed. Muscle disorders in childhood. London, Philadelphia and Toronto: Saunders, 1995: 38–48.
13. Emery A.E.H, Muntoni F. (eds): Duchenne muscular dystrophy. Oxford University Press 2003.
14. Tunca O, Kabaskus N, Herguner O, et al. Alternate day prednisone therapy in Duchenne muscular dystrophy. Neuromuscul Disord 2001;11:630.
15. Yılmaz O, Karaduman A, Topaloğlu H. Prednisolone therapy in Duchenne muscular dystrophy prolongs ambulation and prevents scoliosis. Eur J Neurol 2004;11: 5414.
16. Parreira SL, Resende MB, Zanoteli E et al. Comparison of motor strength and function in patients with Duchenne muscular dystrophy with or without steroid therapy. Arq Neuropsiquiatr. 2010 Oct;68(5):683-8.