O9. Osteoporosis

Patients with COPD are at increased risk for fracture due to the disease itself, the use of high dose corticosteroids and coexisting risk factors such as hypogonadism (induced by corticosteroid therapy itself in high doses in men and women), immobilization reduced muscle mass and other factors.  These patients may have reduced bone mineral density (BMD) due to a reduction in bone formation and perhaps increased bone resporption, the latter being primarily due to the underlying disease itself.

There is little evidence of a deleterious effect of inhaled corticosteroid at conventional doses (<2, 200 mcg/day) on fracture risk.  However, triamcinolone was associated with reduced BMD in the Lung Health Study¹³⁴ [evidence level II].  Australian Guidelines on the prevention and treatment of osteoporosis, including glucocorticoid-induced osteoporosis have been published.¹³⁵ Information on the current subsidies relevant to these drugs can be found on the website of the Pharmaeceutical Benefits Scheme (www.pbs.gov.au/html/healthpro/search/results?atc-code=M05B&publication=GE)  Higher doses of inhaled glucocorticoids are associated with suppressed biochemical markers of remodelling but data on BMD and fractures at these doses are not available¹³⁶ [evidence level I]. 

Despite the lack of evidence, management strategies in individuals taking long term corticosteroid therapy should include investigation of fracture risk including bone densitometry, assessment of vitamin D status, and other risk factors such as coexisting illnesses that may influence the skeleton (e.g. primary hyperparathyroidism).  In individuals with low BMD at onset and in those taking more than 10-15mg of prednisolone per day or who have several risk factors for osteoporosis and whose BMD is <1.5 standard deviations below the young adult mean, treatment should be considered.

Evidence for fracture risk reduction is available for alendronate, risedronate, etidronate and parathyroid hormone.  There is no evidence that calcitriol reduces fracture risk and some evidence to the contrary, so that the use of this drug is not recommended.¹³⁷  However, most patients in these studies did not have respiratory disease.  Although calcium supplementation has not been demonstrated to reduce the risk of fracture in osteoporosis, a reduction in remodelling rate with some possible benefit in slowing bone loss is possible so calcium supplements are appropriate.  Any deficiency of vitamin D should be corrected with supplements.