Natural Progesterone for Osteoporosis Prevention

Ego Seeman, MD, PhD


February 27, 2003


Is there a role for natural progesterone in osteoporosis prevention?

Response from Ego Seeman, MD, PhD

No. The questions of why treat, whom to treat, and what drug to choose are fundamental. Why treat is straightforward. The purpose of treatment is to prevent the morbidity and mortality associated with fractures. Whom and when to treat is complex, and I will not deal with this here. The final question is drug choice, and this is the subject of your question. The answer is easy if we stick to the rules of evidence-based medical research, which provide clarity, but is complex if we break these rules. In terms of osteoporosis prevention, the rules are that drugs must be shown to reduce the risk of fracture in properly designed, executed, presented, and interpreted clinical trials. If this is not done, the drug may well be efficacious, but the evidence is not there one way or another, so the decision of whether to prescribe the drug will be according to feeling-based medicine or opinion-based medicine but not evidence-based medicine.

What are the rules of engagement? Inferences at the end of papers are always made by authors, but the validity of the inference cannot be deduced unless the rules are followed and the data are presented transparently.

The studies must be double-blind and placebo-controlled; they must involve large sample sizes and have few drop-outs; the end points should be numbers of persons with fracture, not numbers of fractures. The primary end points must be predefined and analysis carried out by intention to treat, not post hoc -- ie , the data are examined until something with statistical significance (P < .05) is squeezed out of the data and presented as if it was planned before the study was done. Finally, and perhaps most important, is reproducibility and consistency; the studies should be done by different investigators in different parts of the world and the same result observed. Not following these rules fosters confusion. Most studies don't fulfill all of these criteria, but the best studies follow most. The best studies we have to date are those of alendronate, risedronate, raloxifene, parathyroid hormone, and, more recently, strontium ranelate (the latter results have been presented but are unpublished at this time). The quality of the data for other drugs such as calcitonin, etidronate, menopausal hormone therapy, vitamin D metabolites, and calcium is not as compelling so that inferences are much more difficult to make -- they are made to be sure, but the rules of engagement are incompletely satisfied.

So, that's why the answer to your question is no. I have no idea whether natural progesterone reduces the risk of fracture -- there are no studies to answer this question. So, should you use the drug? In my opinion, a resounding NO.


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