Press release

Debate on bone density testing rages

p. 1253  Women's decisions about hormone replacement therapy after education and bone densitometry — Alexandra Papaioannou, MD, et al [abstract / résumé]

p. 1261  Osteoporosis and bone densitometry: Does the emperor have clothes? — Brian C. Lentle, MD [full text]

After achieving peak bone mass sometime between age 20 and 30, both men and women lose bone at a rate of 0.5% to 1% every year, although there is considerable individual variation. This loss of bone mineral density is known as osteoporosis. Women also go through a phase immediately at and after menopause where they lose bone much more rapidly and are much more susceptible to fragility fractures. Risk assessment has become important because there are now many ways to advise people at risk of fractures.

However, controversy surrounds the test that measures bone mineral density — densitometry — and its use in assessing the risk of osteoporosis in Canada. The Alberta government recently deemed bone densitometry "unsuitable" for screening, while BC has recommended it not be used in "well women". At the core of the debate is the fact that bone density measurements are of limited predictive power and may not be cost-effective if widely used. The Osteoporosis Society of Canada suggests, as does the international community, that physicians should only use bone measurement for people at particular risk of osteoporosis based on more than one historical or lifestyle risk factor.

Dr. Alexandra Papaioannou and colleagues describe a group of women at high risk for osteoporosis who were educated about the use of hormone replacement therapy and subsequently underwent bone densitometry. Dr. Brian Lentle presents both sides of the controversy surrounding bone densitometry testing and concludes that while not perfect, the bone densitometry technology should be used until consensus is reached or new methods emerge.

p. 1245  Adverse effects associated with selective serotonin reuptake inhibitors and tricyclic antidepressants: a meta-analysis — Evelinda Trindade, MD, MSc, et al [full text / résumé]

The 1980s saw the development of a new weapon in the battle against depression: selective serotonin reuptake inhibitors (SSRIs), typified by drugs such as Prozac. These new SSRIs replaced tricyclic antidepressants as the treatment of choice for individuals suffering severe depression. When they were first introduced, SSRIs were touted as being virtually free of side effects — an alternative for those who chose to go off their tricyclic medications because of adverse effects such as nausea or dizziness.

It is now known that there are adverse effects associated with all antidepressants. Reviewing 84 randomized controlled trials reporting on 18 adverse effects, Dr. Evelinda Trindade and colleagues found that tricyclics and SSRIs had comparable rates of adverse effects with similar burden on patients, although the key effects differed between the two drug classes. SSRIs were more likely to precipitate effects such as nausea, anorexia, diarrhea, insomnia, nervousness, anxiety and agitation. Tricyclic antidepressants were more likely to be associated with side effects such as dry mouth, constipation, dizziness, sweating and blurred vision. Quality of life for the individual patient will be something to consider in the choice of drug therapy.

p. 1273  Enzyme replacement therapy for Gaucher's disease: the early Canadian experience — Jennifer J. MacKenzie, MD; Dominick Amato, MD; Joe T.R. Clarke, MD, PhD [abstract / résumé]

Gaucher's disease is a potentially deadly genetic abnormality that severely impairs a patient's ability to break down and properly digest sugars contained in food. It results in massive growth of the spleen and arrested overall growth, and causes severe bony complications. Although very serious, management of the disease has improved dramatically thanks to the development of enzyme replacement therapy with alglucerase.

Intravenous infusions of alglucerase every 2 weeks was almost always beneficial. However, alglucerase, which is derived from human placental material, costs $21 000 per infusion. One year of treatment costs more than $500 000, giving it the dubious honour of being the "most expensive drug in the world". The cost of the treatment and the rarity of the disease (some estimates indicate a prevalence of 1 per 40 000 in the general population) make Gaucher's disease an interesting case study in how governments, insurers and others will face situations where highly effective but highly expensive therapies have been developed.

Although MacKenzie and colleagues found no instances where a patient who needed treatment did not receive it based on an inability to pay, they recommend that reimbursement be standardized across the country based on the application of robust evidence of effectiveness and criteria for disease severity.