Volume 191 - Issue 6
Inappropriate prescribing for osteoporosis
Authors: B E Christopher Nordin and Michael Horowitz
Med J Aust 2009; 191 (6): 355-356. || doi: 10.5694/j.1326-5377.2009.tb02825.x
Published online: 21 September 2009
Published online: 21 September 2009
In reply: Seeman and colleagues agree that most patients with minimal trauma fractures do not have osteoporosis. The figures are clear: only 13% of patients with a peripheral fracture have a hip bone mineral density (BMD) T-score less than or equal to − 2.5 and only 25% have a score less than or equal to − 1.5. The corresponding figures for vertebral fractures are 25% and 38%, respectively.1 We do not argue that the − 2.5 T-score threshold for defining osteoporosis is sacrosanct, but simply that some bone density threshold be defined for subsidised therapy, for which virtually all the supporting evidence is based on treatment of patients with established osteoporosis. Osteopenia is an artificial concept with an arbitrary definition, but we agree that the T-score threshold for subsidised therapy need not be as low in those with prevalent adult fracture as in those without — perhaps − 1.5, which is the threshold recently adopted for patients receiving corticosteroid therapy.
We disagree about the predictive power of bone densitometry; it is comparable to that of blood cholesterol level for heart attacks and blood pressure for stroke.2 It therefore makes sense to measure BMD in all women at menopause and all men at age 60 years to identify those with osteoporosis before they sustain fractures, as well as those with normal but negative T-scores, who have a fracture risk twice that of those with positive T-scores.3 Those with proven osteoporosis could receive subsidised therapy, and those with low normal values could be advised on lifestyle measures, such as calcium supplementation (which significantly delays or prevents bone loss in postmenopausal women).4 People with positive T-scores can be reassured. To suggest that no trials have demonstrated the antifracture efficacy of nutritional measures is to argue against three large meta-analyses showing significant prevention of fractures with vitamin D and calcium supplementation.5-7
The additional cost of confirming low bone density before providing subsidised therapy in fracture cases is likely to be more than offset by the savings from reduced inappropriate therapy; bone densitometry costs about $80 per test, but bisphosphonate therapy costs about $50 a month for each patient. The extra cost of bone densitometry for every woman at menopause and every man at age 60 years could be $20 million a year, but even with subsidised therapy for those without fracture but proven osteoporosis (with a T-score less than or equal to − 2.5, for instance), the cost is also likely to be more than offset in the long term by reducing the enormous cost of osteoporotic fractures ($8 billion annually8). We find it hard to understand why any of our colleagues would not support proposals that would transfer treatment from those who do not need it to those who do.
References
- Stone KL, Seeley DG, Lui L-Y, et al. BMD at multiple sites and risk of fracture of multiple types: long-term results from the study of osteoporotic fractures. J Bone Miner Res 2003; 18: 1947-1954. 0_CBBDFFIG
- Marshall D, Johnell O, Wedel H. Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures. BMJ 1996; 312: 1254-1259. 0_CBBHJCGG
- Abrahamsen B, Rejnmark L, Pors Nielsen S, et al. Ten-year prediction of osteoporosis from baseline bone mineral density: development of prognostic thresholds in healthy postmenopausal women. The Danish Osteoporosis Prevention Study. Osteoporos Int 2006; 17: 245-251. 0_CBBJBIJH
- Nordin BEC. The effect of calcium supplementation on bone loss in 32 controlled trials in postmenopausal women. [Published online ahead of print, Osteoporos Int 21 May 2009.] 0_pgfId-1870592
- Boonen S, Lips P, Bouillon R, et al. Need for additional calcium to reduce the risk of hip fracture with vitamin D supplementation: evidence from a comparative metaanalysis of randomized controlled trials. J Clin Endocrinol Metab 2007; 92: 1415-1423. 0_CBBCEDJA
- Tang BMP, Eslick GD, Nowson C, et al. Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis. Lancet 2007; 370: 657-666. 0_pgfId-1870607
- Bishoff-Ferrari HA, Willett WC, Wong JB, et al. Prevention of nonvertebral fractures with oral vitamin D and dose dependency: a meta-analysis of randomized controlled trials. Arch Intern Med 2009; 169: 551-561. 0_i1091866
- Access Economics. The burden of brittle bones: costing osteoporosis in Australia. Canberra: Access Economics, 2001. http://accesseconomics.com/publicationsreports/getreport.php?report=179&id=227 (accessed Jul 2009).