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PREVENTION OF FRACTURES DUE TO OSTEOPOROSIS (BONE THINNING)
SOME GOOD NEWS

(February 2001)

One of the reasons the Healthful Life Program has been reluctant to make a formal recommendation in regard to osteoporosis (bone thinning) is uncertainty about the criteria for treatment. If older women are divided into quartiles of bone density from strongest (first quartile) to the lowest (fourth quartile), the lowest quartile has a markedly increased risk of fractures, but the second quartile (still above average) and the third quartile (somewhat below average) also have increased fracture risk. The derivative question then is whom do you treat? Do we want three-quarters of older women receiving anti-osteoporosis drugs. One approach to deciding whom to treat is to compare the bone density, by a technique called dual-energy absorptiometry, to that of pre-menopausal women and to use the measurement of standard deviations below the average (up to 2.4 standard deviations below would be moderately low bone density; more than 2.5 standard deviations would be definite osteoporosis with high risk of fracture).

A lot of the answers about whom to treat are provided by an important article published in the Journal of the American Medical Association titled "Effect of Alendronate on Risk of Fracture in Women With Low Bone Density but Without Vertebral Fractures". It is authored by one of the experts in the field, Steven R. Cummings, MD of the University of California and a host of colleagues. Alendronate (trade name Fosamax) is known to reduce the risk of vertebral (spine), hip, and wrist fractures in women with osteoporosis. In this study, 2,214 women were given alendronate, and 2,218 served as controls. They ranged in age from 55 to 80 years. Both groups included women with frank osteoporosis (more than 2.5 standard deviations low) and those with low bone density, but no frank osteoporosis (a situation called osteopenia).

The treatment group and controls were followed for four years. Alendronate increased bone strength (density) of all categories of women regardless of whether the initial bone density at the start was a little low, moderately low,or very low (frank osteoporosis). But, Alendronate did not reduce hip or wrist fracture rates unless the bone density at the start was more than 2.5 standard deviations low (frank osteoporosis). For those women, risk of fracture decreased by 36 percent. If the

bone density was only moderately reduced, Alendronate did not reduce fracture risk. The results for vertebral fractures were a little more complex. For those with frank osteoporosis, the risk reduction was 50 percent. For women with moderately low bone density, the risk reduction was almost as great, but was not statistically significant. For those with only a mildly low bone density, there was no benefit.

Commentary: The authors say that treatment is effective in preventing fractures at a standard deviation of 2.0 below average or worse. That is not exactly what their data show. There was clear benefit in regard to both hip and spine fractures if the initial bone density was 2.5 standard deviations low - that is frank, unequivocal osteoporosis. For those with only moderately or mildly low bone densities, there was no persuasive, statistically significant evidence that Alendronate reduced fracture risk at any of the three major sites - spine, hip, or wrist.

It is important to emphasize that the Alendronate is a relatively new drug and studies are limited, thus far, to four years to seven years of follow up. Nobody knows whether longer treatment will be beneficial, ineffective, or even harmful.

Ratings:

for the benefits of Alendronate in fracture prevention for women with very low bone densities and frank osteoporosis. The evidence now appears persuasive.

for treatment of women with only mild to moderate lowered bone density.

From the health policy point of view, the only women who should be treated with Alendronate after bone density screening are those who are designated as having unequivocal osteoporosis. It may well be that, with longer follow-up periods, Alendronate will turn out to be effective in preventing frank osteoporosis and fractures in women who have osteopenia, not osteoporosis; but, there is no such evidence now.

An unsettled question is how often should bone density tests be done. Healthful Life believes that such testing need only be done primarily to help a woman decide about whether to take medications, and then only once post-menopausally and again at age 60 to 70. If a woman has no intention of taking anti-osteoporosis drugs and will not be influenced by bone density testing, no bone density testing is indicated.

Cummings, S.R., et al. Effect of Alendronate on risk of fracture in women with low bone density but without vertebral fractures. Journal of the American Medical Association. Vol 280. (December 23) Pgs 2077-2082. 1998.

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