Brittle bones: What to do

Recently, a 65-year-old retired math teacher asked whether she really had to take the bone-building drug prescribed by her gynecologist because of an abnormal T-score on a bone densitometry test. "And what's a T-score anyway?" she asked. She had heard a lot about the side effects of those drugs, such as heartburn, ulcers, weakened jawbones, and, paradoxically, leg fractures. She was very leery of embarking on a relationship of five or more years with Fosamax, even though it's available in a less costly, generic version (alendronate).

She showed me her bone-densitometry test results. I noted that the bone-density measurement at her hip site was -2.6, which classifies that joint as osteoporotic, according to a somewhat arbitrary rating system designed by the World Health Organization. A T-score of 1.0 is normal; a score of -1.1 to -2.4 indicates osteopenia (mild bone loss, which is not a disease); a score of -2.5 or greater defines osteoporosis, or brittle bone disease.

Direct-to-consumer ads

The diagnosis of osteoporosis was once made on the basis of the "washed out" appearance of the bone on an X-ray or via an actual bone biopsy. In the late 1980s, the advent of dual-energy X-ray absorptiometry (DEXA) paved the way for a class of drugs called bisphosphonates (such as Actonel, Boniva, and Fosamax). Those drugs were approved not only to treat osteoporosis but also to prevent it. Direct-to-consumer ads proliferated, urging patients to be tested and treated. Some makers of popular bone drugs subsidized the rental of DEXA (or DXA) units for practitioners' offices.

But DEXA results were not the only way to determine a fracture risk. Beyond the usual predictors of age (older than 65), gender (female), race (Asian or Caucasian), low weight, and previous fracture, there were current smoking habits, previous use of corticosteroids, family history of fracture, excessive alcohol use, and rheumatoid arthritis. Additional risk factors included vitamin D deficiency, thyroid or parathyroid hyperfunction, and celiac disease. Factor in causes of repeated falls, such as poor balance and muscle weakness, and you can see that DEXA measurements can often be just one of myriad predictors.

Such was the case with my patient, the math teacher. Except for the T-score of -2.6, she had no risk factors for future fractures. Using a computer tool called FRAX (www.sheffield.ac.uk/frax), developed by the World Health Organization, I was quickly able to determine her 10-year fracture probability. Despite her ominous T-score, according to the FRAX calculation, the likelihood of her having a fracture was only 2.9 percent over the next decade.

Considering her aversion to taking medication and noting studies that determined that cost-effective treatment to prevent future fractures was warranted when the probability was 3 percent or greater, I decided that medication wasn't necessary now. I made sure that her daily calcium and vitamin D intake were adequate, stressed the importance of weight-bearing exercise, and asked her to return in one year for another bone-density test.