May 24, 2004
Current treatment thresholds for preventing osteoporosis-related bone fracture in postmenopausal women were evaluated in a study authored by a physician-scientist at NewYork-Presbyterian Hospital/Columbia University Medical Center and published in the May 24 issue of The Archives of Internal Medicine. The study found that a significant percentage of the 149,524 postmenopausal women enrolled in the National Osteoporosis Risk Assessment (NORA), experienced bone fractures despite having tested with a bone mineral density (BMD) outside of the risk parameters defined by the World Health Organization (WHO) and the National Osteoporosis Foundation (NOF).
In the 12 months following a bone mineral density test (measured by T score) the most important predictor of bone fracture in postmenopausal women without a previous fracture only 18 percent of the 2,259 women who developed fractures of the wrist, forearm, hip, spine, or rib had reported a T score of -2.5 or lower (the definition of osteoporosis according to WHO criteria, and a treatment intervention threshold for many clinicians and reimbursement sources). And, only 45 percent of the women who developed fractures had reported T scores within the more liberal treatment thresholds defined by NOF (a T score of -2.0 or lower, or -1.5 or lower with at least one risk factor).
A strategy to reduce overall fracture incidence will likely require lifestyle changes and a targeted effort to identify and develop treatment protocols for women with less severe low bone mass who are nonetheless at increased risk for future fractures, says Dr. Ethel Siris, director of the Toni Stabile Center for the Prevention and Treatment of Osteoporosis at NewYork-Presbyterian Hospital/Columbia and Madeline C. Stabile Professor of Clinical Medicine at Columbia University College of Physicians Surgeons.
In a companion article, also published in the May 24 issue of The Archives of Internal Medicine, authors, including Dr. Siris, developed a classification system to identify women with osteopenia (T scores of -2.5 to -1.0) who may be at an increased risk of fracture within one year of bone mineral density testing.
The researchers found that osteopenic women with a previous fracture after age 45 had a one-year fracture risk of 4.1 percent, and women with T scores of -1.8 or less or with poor health status had a risk of 2.2 percent. Women with poor mobility had a risk of 1.9 percent. This contracts with a 1.1 percent risk in women with none of these risk factors. Altogether, the researchers' algorithm correctly classified 74 percent of the women who experienced a fracture.
This classification tool [the algorithm] accurately identified postmenopausal women with peripheral T scores of -2.5 to -1.0 who are at increased risk of fracture within 12 months, write the authors. It can be used in clinical practice to guide assessment and treatment decisions.
NORA was funded and managed by Merck Co.,Inc., in collaboration with the International Society for Clinical Densitometry.