Overreliance on T Scores Can Lead to Undertreatment of Those at Risk for Fractures.

VAIL, COLD. -- Dr. Paul D. Miler recently had an office visit from a woman with a history of two vertebral fractures and a hip fracture despite a "normal" bone mineral density T score of -1.4 standard deviations at the femoral neck.

This patient illustrates the folly of single-minded reliance upon T-score thresholds to guide treatment decisions regarding fracture prevention therapy This T-score fixation is followed by many physicians and encouraged by National Osteoporosis Foundation guidelines that base treatment recommendations on T scores. The problem is that the strategy results in undertreatment of an enormous number of women at high fracture risk, said Dr. Miller, medical director of the Colorado Center for Bone Research, Lakewood.

"I have a lot of problems with the National Osteoporosis Foundation treatment guidelines based on bone mineral density," he said at a conference on obstetrics and gynecology sponsored by the University of Colorado.

It's important to recognize that although a low bone mineral density (BMD) T score is a powerful predictor of increased hip fracture risk, with an odds ratio of 2.6 in one major study, it's hardly the only one. After adjusting for BMD there remain a large number of other independent risk factors for hip fracture.

Dr. Miller's patient with three prior fractures possessed some of them. She was a current smoker and had a long hip axis length, a Colles' fragility fracture after age 45, and a maternal history of hip fracture.

Other independent risk factors for hip fracture include elevated biochemical markers of bone turnover, body weight less than 127 pounds, poor visual acuity, poor depth perception due to macular degeneration, low gait speed, and increased body sway. "As risk factors accumulate, the threshold for treatment has got to change. I don't want people to get locked into the idea that if the T score isn't below -2 standard deviations that you shouldn't treat, he stressed.

Osteoporosis experts haven't done a good job of integrating these clinical risk factors into treatment decision making, he admitted, but that's about to change. In the coming months, look for ...