Osteoporosis Drugs - Controversies & Challenges

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Women's Health Activist Newsletter
September/October 2008

NWHN has had its “watchdog” eye on osteoporosis for over 25 years. During that time, the condition has gone through a pendulum swing – first it was ignored by all but a few specialists, now it’s falsely promoted as a threat to every middle-aged woman. Over the years, NWHN has produced a series of fact sheets, investigative articles, book chapters and position papers about various aspects of osteoporosis. This article contains material from our latest Fact Sheet. In it, we caution women to be wary of osteoporosis drugs for prevention. They can help some women, but are often prescribed to women who are more likely to be harmed than helped.

What is Osteoporosis?

Osteoporosis literally means “porous bone”. A person’s bones change throughout life, as a natural process breaks down and builds bones up at the microscopic level. Children and young adults build more bone than they break down. After age 35—40, breaking down exceeds building up, and all adults start to lose bone. For a few years around menopause, women lose bone more quickly, possibly because they no longer need extra stores of minerals to support a developing fetus. Osteoporosis occurs when the natural aging process goes too far and bones become weak and fragile; the most harmful fractures usually occur after age 70. Osteoporosis has several causes, which include age, certain medications (like steroids), and inactivity. Removing a woman’s ovaries also increases her risk of osteoporosis.

People with osteoporosis are at greater risk for bone fractures, especially in the hip, spine, and wrist. Hip fractures lead to hospitalization and can take a long time to heal; many women never fully recover from such a fracture. Individual vertebral fractures can be completely painless and cause no problems at all, but, if multiple fractures develop in the spine, it can be very painful and restrict the person’s movement.

Osteoporosis Screening

In the 1980s, women’s health advocates were concerned that the medical community had overlooked the effect of bone fractures on older women’s quality of life. We advocated for change — but the pendulum has swung to the other extreme. A decade-long program by big drug companies has marketed osteoporosis as a disease that not only affects older women, but one that should also be of concern to middle-aged women. Despite the fact that independent medical experts recommend women not be screened for osteoporosis until age 65 (unless there is an unusual risk factor like long-term steroid use), osteoporosis screening is now widely promoted by physicians and drug companies for women in their 50s and even 40s.

The most common screening tool is a DEXA X-ray scan, which measures bone mineral density (BMD) in the hip or spine. DEXA results (called “T scores”) compare a middle-aged woman’s bone density to that of a healthy young adult (almost guaranteeing the scan will reveal bone loss, since everyone loses bone with age). A woman whose bone density is significantly lower than a young adult’s is diagnosed with osteoporosis. Some clinicians are now telling women with bone density that is only slightly lower than the young adult average that they have “osteopenia” — a term that describes reduced bone density but is neither a disease nor a disorder.

DEXA machines are safe and pose no health risks, but the push to use them among younger women and diagnose osteopenia can lead to early and unnecessary treatment. As a result, women risk taking expensive drugs for decades that may have serious risks and/or side effects. Moreover, while the scan can predict fracture risk in the short-term, it cannot accurately predict the risk of fracture occurring far in the future; thus, a scan taken at age 45 generally has no value for predicting what may occur when the woman is 70 (when debilitating fractures are most likely to occur).

In addition, the accuracy of DEXA machines may not be as good in real life as it has been shown to be in carefully controlled research settings. Specialists have observed that very small changes in positioning of the hip and spine for BMD studies result in large differences in T scores. There is also a lot of variation between machines even from the same manufacturer. We recommend that, if possible, BMDs be done on the same machine. All this highlights the fact that margin of error of the BMD machines is similar to changes in bone density — so fewer studies done at greater intervals (on the same machine!) are better.

Questions also exist about the value of such screening for women of color. The original DEXA studies did not include any women of color, so there’s a lack of good information about normal bone density scores, and what score might indicate concern about the risk of bone fractures, for these populations. African American women typically have denser bones and lower fracture rates than White women, while Asian American women typically have thinner bones, but also lower fracture rates, than White women. NWHN believes that research on both osteoporosis and on DEXA scans should take these differences into account; until then, women of color should approach screening with caution.

Drug Treatments

Women diagnosed with osteoporosis or osteopenia are usually told they need to take prescription medication to prevent further bone loss and reduce the risk of fractures. The most common drugs are:

Hormones: The Food and Drug Administration (FDA) has approved estrogen and progestin treatment to prevent osteoporosis, but not to treat it. Both estrogen alone and combinations of estrogen and progestin reduce women’s risk of osteoporosis and bone fracture. But, the hormones also increase the risk of breast cancer, heart attack, stroke, and pulmonary embolism. So, these hormones should be the last choice for osteoporosis prevention and should be used only when other prevention methods are contraindicated.

Two other hormones have been approved to treat osteoporosis: teriparatide and calcitonin. Teriparatide (brand name: Forteo) is a derivative of human parathyroid hormone (PTH), the primary regulator of calcium and phosphate metabolism in bones; a daily 20 mg injection has been shown to stim-ulate new bone formation and prevent vertebral and non-vertebral fractures in women with osteoporosis. Teriparatide is generally used only for women with severe osteoporosis, as treatment involves taking daily injections and side effects can include nausea, leg cramps, and dangerously high calcium levels.

Calcitonin (brand names: Fortical or Miacalcin; not the same as calcium supplements) has been shown to prevent fractures of the spine but not of non-vertebral bones (e.g. hip, wrist). Calcitonin is approved to treat women with osteoporosis, but its approval was based on weaker evidence than more recently approved drugs, and its use is not generally recommended. Women who take calcitonin must watch their intake of foods with high calcium levels (e.g., milk, cheese), as excessive calcium can be dangerous. Calcitonin is administered through a nasal spray; side effects may include nasal congestion and nausea.

Bisphosphonates: The FDA has approved six bisphosphonates to prevent bone loss and fractures in post-menopausal women: alendronate (Fosamax), etidronate (Didronel), ibandronate (Boniva), risedronate (Actonel), tiludronate (Skelid), and zoleldronic acid (Reclast, Zometra). Some are taken daily, others are formulated for weekly or monthly use. Bisphosphonates seem to have fewer risks than hormones, but haven’t been around very long; little is known about either the effects of taking them for more than 10 years, or their use in pre-menopausal women. We now know that the fracture prevention benefit of at least one bisphosphonate (alendronate) persists for many years after stopping the drug. But, whether it could last long enough to reduce the risk of fractures in old age is unknown.

Several possible health problems are associated with bisphosphonates. The FDA expects to release findings later this year from a safety review of the drugs, initiated after studies reported that women taking them had higher rates of irregular heart rhythms (atrial fibrillation) than other women. Second, women may experience severe bone, joint, and/or muscle pain after starting a bisphosphonate. The FDA advises patients with such pain to consider discontinuing the drug, which usually causes the pain to go away. Third, there have been reports that the jaw tissue of some women taking bisphosphonates dies (jaw necrosis), which can necessitate removal of the jaw bone. Finally, bisphosphonates can cause severe heartburn and ulcers and damage the stomach and esophagus if not taken in a very careful regimen (on an empty stomach, with a full glass of water, while sitting upright for up to an hour).

Selective Estrogen Receptor Modulators: The FDA’s approved raloxifene (Evista) to prevent and treat osteoporosis. The drug has been tested more extensively than biophosphonates and, although it reduces the risk of vertebral fractures, it doesn’t seem to reduce hip fracture risk. It also has different safety concerns that include increased risks of blood clots, hot flashes, nausea, and leg cramps.

Alternatives

Other promising interventions focus on preventing fractures: balance training reduces the risk of falling, which is often responsible for broken bones in older people, and hip protectors seem to reduce the risk of fracture when falls happen. Other practical ways to reduce the risk of falling include making sure that vision prescriptions are up-to-date, checking prescriptions for drug interactions that might cause dizziness, eliminating fall-causing hazards in the home (like slippery rugs), wearing appropriate shoes.

The Bottom Line

Drug companies are clearly trying to expand the market for osteoporosis drugs; their latest efforts target “non-traditional” populations (like younger women and men) for screening. As a result, many women under age 65 without critical risk factors are being screened for osteopenia and osteoporosis, despite the fact that early screening hasn’t been shown to prevent most serious fractures. The NWHN encourages women under age 65 to reject bone density screening unless they have unusual circumstances that increase their risk.

Women also need to consider other issues when deciding whether to take osteoporosis drugs. The treatment’s duration is critical in determining its effectiveness: when a woman stops taking certain osteoporosis prevention drugs, the preventive effects are quickly lost. Don't hesitate to ask your health care provider about the safety and efficacy of any osteoporosis medication, and whether non-drug alternatives might be just as effective, based on your personal history and current health status. For more information go to the NIH Osteoporosis and Related Bone Diseases Resource Center's website.

This article was excerpted from the NWHN Osteoporosis Fact Sheet.

 

 

REFERENCE

1. Osteoporosis Prevention, Diagnosis, and Therapy, NIH Consensus Statement On-line: March 27-29 2000; 17(1): 1-36. Visited 8/15/08.