Association between Osteoporosis Screening and Hip Fracture Rates in Adults 65 Years of Age and Older

Summaries for Patients are a service provided by Annals to help patients better understand the complicated and often mystifying language of modern medicine.

Summaries for Patients are presented for informational purposes only. These summaries are not a substitute for advice from your own medical provider. If you have questions about this material, or need medical advice about your own health or situation, please contact your physician. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the American College of Physicians.

The summary below is from the full report titled "Association between Screening for Osteoporosis and the Incidence of Hip Fracture." It is in the 1 February 2005 issue of Annals of Internal Medicine (volume 142, pages 173-181). The authors are L.M. Kern, N.R. Powe, M.A. Levine, A.L. Fitzpatrick, T.B. Harris, J. Robbins, and L.P. Fried.

What is the problem and what is known about it so far?

Osteoporosis is a condition in which bones become less dense and bone fractures occur more easily. Two approaches help prevent osteoporosis-related fractures. One is to promote measures that can prevent osteoporosis itself, such as adequate calcium and vitamin D intake, physical activity, and avoidance of tobacco and alcohol. Some drugs, such as estrogen and bisphosphonates, can also prevent osteoporosis, but experts do not recommend these drugs for general use because of side effects and expense. The second approach is to test for osteoporosis in order to identify people with low bone density. These people are at highest risk for fracture and will benefit most from drugs that prevent fracture. Testing for osteoporosis involves using a special test called dual-energy x-ray absorptiometry (DEXA). Although some groups recommend osteoporosis screening, no study has proven that osteoporosis screening reduces fractures.

Why did the researchers do this particular study?

To see whether people who get osteoporosis screening have lower rates of hip fractures than people who do not get screening.

Who was studied?

3107 adults (about half of them were men and half were women) 65 years of age and older who were participating in a large study of cardiovascular health. The researchers excluded people who had known osteoporosis, had had a previous hip fracture, or were taking bisphosphonate drugs.

How was the study done?

The study included people from 4 geographic areas: California, Pennsylvania, Maryland, and North Carolina. The study patients from California and Pennsylvania had DEXA scans to measure bone density. The researchers sent the results of the DEXA scans to patients and their primary care doctors. The researchers left the prescription of any osteoporosis treatment up to the patients and their doctors. The researchers followed patients for up to 6 years and collected information about hip fractures by using hospital records.

What did the researchers find?

Hip fractures occurred in 33 screened patients (about 5 fractures per 1000 person-years) and 69 usual care patients (about 8 fractures per 1000 person-years). This result was statistically significant, but analyses showed other differences besides screening between the groups that could explain the differences in hip fracture. Surprisingly, differences in the prescription of vitamin D, calcium, estrogen, and bisphosphonates between the screened and unscreened groups did not seem to account for all of the differences in hip fractures.

What were the limitations of the study?

Screening in the study occurred in 1994, and the use of bisphosphonates has increased since then. The researchers did not collect information on changes in exercise and behaviors to prevent falls that might have accounted for some of the benefit among screened patients. The study examined only hip fractures and included both men and women. The results might be different if they examined only women or looked for fractures in other locations.

What are the implications of the study?

This study is not definitive proof, but it is the best available evidence that screening for osteoporosis prevents fractures.

Read all Rapid Responses

Screening risk of fracture in Osteoporosis

Francisco R. Lafita, et al.

Annals Online, 8 Feb 2005 [Full text]