SACRAMENTO, California—A new algorithm based on 11 clinical factors is readily available on the Internet and can predict the 5-year risk of hip fracture among postmenopausal women, John Robbins, MD, and colleagues report in this week's JAMA.¹

"Knowing the 5-year risk of fracture will permit patients and physicians to make informed choices when balancing lifestyle changes against undergoing medical interventions. Publication of these results, along with the user-friendly tool for their application, will permit others to rapidly test their utility. However, we believe 11 readily available clinical variables offer a simple means of stratifying the 5-year risk of hip fracture in postmenopausal women," said Dr. Robbins, from the department of internal medicine at the University of California at Davis School of Medicine in Sacramento.

Easy to use online tool

The new algorithm is expected to have utility as a low-cost screening tool because it does not require dual-energy X-ray absorptiometry (DXA) scanning and because it can be readily used online at: http://hipcalculator.fhcrc.org.

The algorithm was developed based on data for more than 100,000 postmenopausal women who participated in the observational component of the Women's Health Initiative (WHI) or in a clinical trial of hormone therapy. During a follow-up of 7.6 years there were 1132 hip fractures among these women.

Eleven factors were associated with a high risk of hip fracture during the next 5 years: age, self-reported health, weight, height, race/ethnicity, self-reported physical activity, history of fracture after age 54 years, parental hip fracture, current smoking, current corticosteroid use, and diabetes treated with medications. Physical activity was measured as metabolic equivalent tasks.

Accuracy similar to DXA

The predictive accuracy of the algorithm was similar to that for DXA. For example, the 5-year hip fracture rates were 3.8% in the high-risk DXA group (T-score <e;-2.5) and 3.1% in the high-risk point-score group (>e;21 points).

The investigators stress that the population included women from diverse racial and ethnic groups. "This algorithm, based on 11 clinical factors, may be useful to predict the 5-year risk of hip fracture among postmenopausal women of various ethnic backgrounds," they write. They also suggest that prior studies associating the risk of hip fracture with specific ethnic groups "may have identified a marker of risk not a cause because they failed to adjust for such factors as weight, smoking status, and other risks."

Among the variables that were considered but were not predictive of hip fracture risk were education, cups of regular coffee, age at menopause, age at first birth, maintaining a lactose-free diet, pulse pressure, intentional weight loss of >e;10 lb, and use of vitamin D supplement, multivitamins, thiazides and thiazide-like diuretics, antihypnotics, benzodiazepines, antiestrogens, calcitonins, and oral contraceptives.

Dr. Robbins emphasized that the new approach requires further testing to determine clinical utility. "This study does not indicate whether women defined by the WHI algorithm to be at risk would benefit from measures to prevent hip fracture in contrast to those trials that have used DXA T-scores as a criterion for treatment. Some women who would be classified as high risk (point score >21) in our study did not have low T-scores."

Points Score for Hip Fracture Risk Factors

Risk Factor	Point Score
Age	0.5 point per year >50
Self-reported health:
Fair or poor	3
Good	1
Very good or excellent	0
Height	0.5 per inch >64
Weight	1 per 25 lb >200
Fracture >e;age 55	2
Race/ethnicity	3 if white
Physical activity	1 if <12 metabolic equivalent tasks
Current smoker	3
Parent broke hip	1
Corticosteroid use	3
Hypoglycemic agent use	2

Source: Adapted from Robbins J, et al.¹

5-Year Hip Fracture Risk and Risk Factor Point Scores

Point Score Total	5-Year Hip Fracture Risk (%)
9	0.1
18	1
24	5

Source: Adapted from Robbins J, et al.¹

Reference