Corticosteroid-induced osteoporosis: guidelines for prevention--are they useful?

INTEREST in corticosteroid-induced osteoporosis (CIOP) has been enhanced recently by medico-legal concerns and by the publication of studies indicating the potential for prevention and treatment. The diculties in management induced by these two factors have spurned the development of guidelines for prevention and treatment in the UK [1] and the USA [2]. This brief review will assess the similarities and dierences between the advice given in the two publications for prevention, and examine their relevance to practice today. One of the principal concerns raised by the decision-making algorithms is how best to diagnose CIOP. Clearly, it would be ideal to make the diagnosis before fracture as this may occur within a few weeks of onset of therapy and may be present in up to 30±40% of patients with asthma [3] and rheumatoid arthritis [4]. However, although bone mass measurements ®gure prominently in both sets of guidelines, there are, as yet, no prospective data indicating that they predict osteoporotic fractures in patients receiving corticosteroids. Indeed, there is some evidence that bone mineral density (BMD) measurements are relatively higher in those who sustain vertebral fractures while receiving glucocorticoids compared to those with post-menopausal vertebral fractures [5]. This has led a group advising on the necessary registration requirements for drugs for CIOP to suggest a higher cut-o for the bone density diagnosis of CIOP, i.e. >1.5 S.D. below the young normal mean [6], compared to >2.5 S.D. for the diagnosis of post-menopausal osteoporosis [7]. The need for guidance on prevention has been highlighted by recent observational studies indicating that only 8% [8] to 14% [9] of patients who are receiving oral corticosteroids receive any preventative therapy. However, it is likely that using preventative therapies in all who are to receive long-term corticosteroids would be prohibitively expensive. It is, therefore, important to contemplate whether we should be targeting therapy by the use of the published guidelines. However, the two dierent versions are not identical. The British guidelines were published following a consensus meeting of a group of osteoporosis experts [1], while the US recommendations were published by the American College of Rheumatology Task Force on Osteoporosis Guidelines [2]. Neither, therefore, can be considered to have met the criteria for the preparation of guidelines as suggested by the Scottish Integrated Guideline Network [10]. Both sets of guidelines agree that all patients receiving corticosteroids should be given lifestyle advice, including exercise, despite a lack of evidence that such advice is eective even in post-menopausal osteoporosis, never mind CIOP. Both groups also indicate the value of measurement of BMD of the spine and hip. Appendicular measurements of bone mass are not advised by either group, partly because corticosteroid eects are likely to be more marked at axial sites with a high proportion of trabecular bone and also because the eects of the drugs might be hidden by local bone loss in patients treated for in ̄ammatory joint disease. The intervention thresholds, however, dier considerably. Eastell's group [1] suggest that intervention be targeted at those patients, both men and women, whose BMD is e1 S.D. below the age-matched mean at spine or hip (or >2.5 S.D. below the young normal mean), although they also suggest intervention in patients who are likely to be on >15 mg of prednisolone or equivalent per day, while the US group suggest calcium and vitamin D for all, despite the controversy as to whether this is eective [11, 12], and additional intervention with hormone replacement therapy (HRT) for post-menopausal women, oestrogencontaining oral contraceptives in premenopausal women and testosterone if serum levels are low in men. The interventions advised are similar in the UK guidelines with respect to HRT, despite the lack of anything other than a cohort study to substantiate the advice [13], and testosterone in men, which has recently been shown to be eective in a randomized controlled trial (RCT) [14]. Both groups advise alternative strategies for those unable or unwilling to take HRT and the advised alternatives include switching from prednisolone to de ̄azacort (UK only), the use of a bisphosphonate (UK and USA), calcitriol (UK only) and calcitonin (US only). De ̄azacort has recently been marketed in the UK, although not with a bone-sparing licence perhaps because of its controversial eects on bone [15, 16]. Calcitriol has been advised in the UK because of its success in preventing spinal bone loss in the largest primary prevention RCT to date [17]. However, the US/ACR group mention it only as an aside, but perhaps do not recommend it speci®cally because of the need to monitor serum calcium. Nasal calcitonin does not receive a mention in the UK, partly because only observational data were available at the time of publication (although an RCT has been published more recently [18]), but also because it is only available as a parenteral preparation, whereas in the US it is marketed as a nasal spray. No speci®c British Journal of Rheumatology 1997;36:1035±1037