Volume 191 - Issue 6
Inappropriate prescribing for osteoporosis
Authors: Ego Seeman, Mark A Kotowicz, Peter T Nash and Philip N Sambrook
Med J Aust 2009; 191 (6): 355-356. || doi: 10.5694/j.1326-5377.2009.tb02824.x
Published online: 21 September 2009
Published online: 21 September 2009
To the Editor: Nordin and colleagues raised important issues about prescribing for osteoporosis.1 We agree that the Pharmaceutical Benefits Schedule guidelines for therapy are imperfect, but they do not necessarily lead, as Nordin et al claim, to inappropriate prescribing. For historical reasons, osteoporosis is held to be synonymous with vertebral fractures, but this misrepresents the epidemiology of fractures. Non-vertebral fractures account for 80% of all fractures and 90% of the loss of quality of life and economic costs. Vertebral fractures contribute only 20% of the burden.2 Most fractures arise in the large population at moderate risk with osteopenia — the “bell” of the Gaussian bone mineral density (BMD) distribution, not its “tail”, which comprises those with osteoporosis (defined by a bone densitometry T-score less than – 2.5). Concentrating on vertebral fractures and screening for osteoporosis with bone densitometry, as recommended by Nordin et al, is no solution to this public health problem.
Nutritional change and exercise are appealing because they are safe and cost-effective approaches for early intervention, but are supported only by level D evidence (expert opinion).3 Although these approaches are plausible, no trials demonstrate their antifracture efficacy. There are no means of early identification of individuals who will sustain a fracture. Densitometry is neither sensitive nor specific for fracture; most people with osteoporosis do not sustain a fracture, and most fractures arise in people without osteoporosis, who would, paradoxically, be excluded from treatment by screening.4 Bone densitometry should be more accessible for case finding, but its use for screening does not reduce the fracture burden because of this screening paradox. However, Medicare reimbursement for densitometry is available for high-risk individuals (those with premature menopause, other illnesses or who are taking corticosteroids), not just for those aged over 70 years or those with fractures. Restricting treatment on the basis of BMD results is not advocated by the Australian and New Zealand Bone and Mineral Society precisely because it excludes this moderate-risk group from treatment, particularly those with fractures and osteopenia.
There is level A evidence (meta-analysis of multiple randomised trials)5 for the antifracture efficacy of bisphosphonates in patients with osteoporosis, and evidence based on single trials6 of their antifracture efficacy in those with osteopenia and prevalent fractures, whose fracture risk is similar to that of people with osteoporosis and no prevalent fracture. There is limited evidence of antifracture efficacy of bisphosphonates in individuals with osteopenia alone.6 Preventing the first fracture is important, and guidelines are deficient in this way. Case finding to estimate absolute risk is the best approach available at this time, using risk factors, remodelling markers and, more recently, microstructural analysis to improve sensitivity and specificity.
Rather than inappropriate or overprescribing, evidence suggests underutilisation of drug therapy for osteoporosis.7,8 Osteoporosis remains underdiagnosed, underinvestigated and undertreated, and limiting access to bone densitometry is not supported by the Australian and New Zealand Bone and Mineral Society.
Competing interests
Ego Seeman serves on the medical advisory committees of and has received speaker fees from Amgen, Eli Lilly, Merck Sharp and Dohme, Novartis, Procter and Gamble, Sanofi-Aventis and Servier. Mark Kotowicz serves on the Novartis Alcast medical advisory board and has received speaker fees and travel assistance from Merck Sharp and Dohme, Sanofi-Aventis and Servier. Peter Nash received research funding for clinical trials, and honoraria for advice from Eli Lilly, Merck Sharp and Dohme, Novartis, Sanofi and Servier, and has also lectured on their behalf. Philip Sambrook serves on the medical advisory boards of and has received speaker fees from Amgen, Merck Sharp and Dohme, Novartis, Sanofi-Aventis and Servier.
References
- Nordin BEC, Horowitz M, Chatterton BE. Inappropriate prescribing for osteoporosis [letter]. Med J Aust 2009; 190: 519-520.
- Johnell O, Kanis JA. An estimate of the worldwide prevalence and disability associated with osteoporotic fractures. Osteoporos Int 2006; 17: 1726-1733. 0_i1091867
- Royal Australian College of General Practitioners. Osteoporosis clinical guideline April 2008 draft. http://www.racgp.org.au/Content/NavigationMenu/ClinicalResources/RACGPGuidelines/Arthritis/OPguideline.pdf (accessed Aug 2009).
- Rose G. Sick individuals and sick populations. Int J Epidemiol 1985; 14: 32-38. 0_i1091871
- MacLean C, Newberry S, Maglione M, et al. Systematic review: comparative effectiveness of treatments to prevent fractures in men and women with low bone density or osteoporosis. Ann Intern Med 2008; 148: 197-213. 0_i1091873
- Seeman E, Devogelaer JP, Lorenc R, et al. Strontium ranelate reduces the risk of vertebral fractures in patients with osteopenia. J Bone Miner Res 2008; 23: 433-438. 0_i1091875
- Eisman J, Clapham S, Kehoe L. Osteoporosis prevalence and levels of treatment in primary care: the Australian BoneCare Study. J Bone Miner Res 2004; 19: 1969-1975. 0_i1091877
- Chen JS, Hogan JC, Lyubomirsky G, Sambrook PN. Management of osteoporosis in primary care in Australia. Osteoporos Int 2009; 20: 491-496. 0_i1091880