Association between Screening for Osteoporosis and the Incidence of Hip Fracture

1 February 2005 | Volume 142 Issue 3 | Pages 173-181

Background: Because direct evidence for the effectiveness of screening is lacking, guidelines disagree on whether people should be screened for osteoporosis.

Objective: To determine whether population-based screening for osteoporosis in older adults is associated with fewer incident hip fractures than usual medical care.

Design: Nonconcurrent cohort study.

Setting: Population-based cohort enrolled in the Cardiovascular Health Study (CHS) from 4 states (California, Pennsylvania, Maryland, and North Carolina).

Patients: 3107 adults 65 years of age and older who attended their CHS study visits in 1994–1995.

Measurements: 31 participant characteristics (including demographic characteristics, medical histories, medications, and physical examination findings) and incident hip fractures over 6 years of follow-up.

Intervention: Bone density scans (dual-energy x-ray absorptiometry [DEXA] at the hip) for participants in California and Pennsylvania (n = 1422) and usual care for participants in Maryland and North Carolina (n = 1685).

Results: The incidence of hip fractures per 1000 person-years was 4.8 in the screened group and 8.2 in the usual care group. Screening was associated with a statistically significant lower hazard of hip fracture than usual care after adjustment for sex and propensity to be screened (Cox proportional hazard ratio, 0.64 [95% CI, 0.41 to 0.99]).

Limitations: The mechanism of the association was unclear. A small unmeasured confounder that decreased the hazard of hip fracture could diminish or erase the observed association.

Conclusions: Use of hip DEXA scans to screen for osteoporosis in older adults was associated with 36% fewer incident hip fractures over 6 years compared with usual medical care. Further research is needed to explore the mechanism of this association.

Editors' Notes Context Although some groups, such as the U.S. Preventive Services Task Force and National Osteoporosis Foundation, advocate screening for osteoporosis, direct evidence that screening reduces fractures is lacking. Contribution In this observational study, receipt of bone density scans was associated with a lower hip fracture rate (4.8 per 1000 person-years vs. 8.2 per 1000 person-years), and this difference was statistically significant even after adjustment for sex and propensity to be screened. Surprisingly, differences in osteoporosis treatments between the screened and unscreened groups did not seem to account for all the differences in hip fractures, so the mechanism of the association is unclear. Cautions The association was tenuous, and a small, unmeasured confounder could explain it. However, this study presents the best available evidence for the effectiveness of osteoporosis screening. –The Editors

 

Author and Article Information

From Robert Wood Johnson Clinical Scholars Program, Johns Hopkins School of Medicine, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; University of Washington, Seattle, Washington; National Institute on Aging, Bethesda, Maryland; and University of California, Davis, Sacramento, California.

Acknowledgments: The authors thank Leon Gordis, MD, DrPH, for his thoughtful review of the research proposal.

Grant Support: The Cardiovascular Health Study was funded by the National Heart, Lung, and Blood Institute (contracts N01-HC-85079 through N01-HC-85086, N01-HC-35129, and N01-HC-15103). For a full list of participating CHS investigators and institutions, see http://128.208.129.3/chs/pi.htm. The bone density scans were funded by the National Institute on Aging (intra-agency agreements Y02-AG-4-0251 and 1-Y02-HC-40205). Dr. Kern (maiden name, Korn) was supported as a fellow in the Robert Wood Johnson Foundation Clinical Scholars Program at the time this study was conducted. Dr. Powe is supported in part by the National Institute of Diabetes and Digestive and Kidney Diseases (grant K24DK02643).

Potential Financial Conflicts of Interest: Honoraria: M.A. Levine (Merck & Co. Inc., Lilly Research Laboratories, Procter & Gamble); Stock ownership or options (other than mutual funds): M.A. Levine (Merck & Co., Inc.); Other: J. Robbins (Novartis, Wyeth).

Requests for Single Reprints: Lisa M. Kern, MD, MPH, Department of Public Health, Weill Medical College of Cornell University, 411 East 69th Street, Room KB-311, New York, NY 10021; e-mail, lmk2003{at}med.cornell.edu.

Current Author Addresses: Dr. Kern: Department of Public Health, Weill Medical College of Cornell University, 411 East 69th Street, Room KB-311, New York, NY 10021.

Dr. Powe: Welch Center for Prevention, Epidemiology & Clinical Research, Johns Hopkins Medical Institutions, 2024 East Monument Street, Suite 2-600, Baltimore, MD 21205.

Dr. Levine: The Children's Hospital, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Mailcode A120, Cleveland, OH 44195.

Dr. Fitzpatrick: Collaborative Health Studies Coordinating Center, University of Washington, Box 354922, Building 29, Suite 310, 6200 NE 74th Street, Seattle, WA 98115.

Dr. Harris: Laboratory of Epidemiology, Demography and Biometry, National Institute on Aging, Gateway Building, Suite 3C309, 7201 Wisconsin Avenue, MSC 9205, Bethesda, MD 20892.

Dr. Robbins: Department of Internal Medicine, Division of General Internal Medicine, University of California, Davis, 4150 V Street, Suite 2400, Sacramento, CA 95817.

Dr. Fried: The Johns Hopkins Center on Aging and Health, 2024 East Monument Street, Suite 2-700, Baltimore, MD 21205.

Author Contributions: Conception and design: L.M. Kern, N.R. Powe, L.P. Fried.

Analysis and interpretation of the data: L.M. Kern, N.R. Powe, A.L. Fitzpatrick, L.P. Fried.

Drafting of the article: L.M. Kern, M.A. Levine, T.B. Harris.

Critical revision of the article for important intellectual content: L.M. Kern, N.R. Powe, M.A. Levine, A.L. Fitzpatrick, T.B. Harris, J. Robbins, L.P. Fried.

Final approval of the article: L.M. Kern, N.R. Powe, M.A. Levine, A.L. Fitzpatrick, T.B. Harris, J. Robbins, L.P. Fried.

Provision of study materials or patients: T.B. Harris, J. Robbins, L.P. Fried.

Statistical expertise: N.R. Powe, A.L. Fitzpatrick.

Obtaining of funding: T.B. Harris, J. Robbins.

Administrative, technical, or logistic support: N.R. Powe, M.A. Levine.

Collection and assembly of data: N.R. Powe, T.B. Harris, J. Robbins.

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