Report of a Muscular Dystrophy Campaign funded workshop Birmingham, UK, January 16th 2004. Osteoporosis in Duchenne muscular dystrophy; its prevalence, treatment and prevention

R. Quinlivan, H. Roper, M. Davie, N.J. Shaw, J. McDonagh, K. Bushby - UK

Neuromuscular Disorders, 2004

11. Conclusions and recommendations

11.1. DMD and osteoporosis

Duchenne muscular dystrophy leads to reduced mobility, which is associated per se with an increased chance of fractures and reduced bone mineral density. Bone mineral density, especially in the spine is further reduced by longterm steroid treatment. The development of vertebral fractures is dependent upon the cumulative steroid dose and the risk may be very high for those children receiving long-term steroids. The investigation of bone mineral density in children can be problematic and care is needed in the interpretation of data, however, individual children can act as their own controls. DXA scanning can therefore be used to monitor bone mineral density in an individual patient, but there is no clear relationship between a particular Z score and risk of fracture, and DXA results alone should not be used to change practice or lead to specific treatment. When developing randomised controlled treatment trials, different centres may not have compatible DXA machines or software but this can be often overcome using statistical methods for correction.

11.2. Prevention of complications

Fig. 1 is a schematic outline of the proposed management plan agreed by the group. Preserving muscle function will protect long bones, prolonging walking and standing is an important element of management. Sunshine and nutrition are extremely important in maintaining healthy bones and care must be taken to ensure optimal exposure. There is a lack of published evidence for the prevention of vertebral fractures using calcium and vitamin D supplements, there is no evidence based indication to prescribe supplements alongside steroids unless there is a demonstrated deficiency or unless dietary manipulation is not possible.

When commencing steroids in children with DMD, it is prudent to check the 25OH vitamin D levels before treatment. All children should be referred to a dietician in order to optimise the dietary calcium and vitamin D intake. If the 25OH vitamin D levels are low, the clinician may wish to consider treatment with calcium and vitamin D supplements. A baseline DXA scan to assess bone mineral density is probably advisable with follow up scans every 1–2 years, however, at the moment there is no consensus on how to manage worsening bone mineral density in an individual child in the absence of a vertebral fracture. More research is required to establish the long-term effects of bisphosphonates in children, the most effective dose and frequency of treatment, especially oral treatment, before they can be recommended for prophylactic use.

11.3. Treatment of complications

Any patient receiving steroids who complain of back pain should have X-rays (Anterior, Posterior, and Lateral) of the spine taken and if a vertebral fracture is evident urgent referral to a metabolic bone specialist for intravenous bisphosphonate treatment is indicated. Under these circumstances it is not necessary to stop steroid treatment. In the presence of a long bone fracture, a common complication in DMD, no pharmacological treatment is required unless a silent vertebral fracture is discovered on a lateral spine X-ray.