Evaluation And Management Of Hip Fracture Risk In The Aged
Published 2012 · Medicine
Hip fractures are common and a major national health concern. According to the National Center for Health Statistics,1 in 2004, there were more than 320,000 hospital admissions for hip fractures. The first year death rate after hip fracture is approximately 30%, which is above that of age-matched controls2 and remains increased compared with age-matched controls even after 10 years of follow-up. Although some studies have suggested a recent decline in the incidence and mortality related to hip fractures after adjusting for the increasing age of the U.S. population,3,4 the sheer growth in the segment of our population most vulnerable to hip fracture, those older than 80 years, will continue to grow more rapidly than any other segment of our population during the next 3 decades. By 2040, it has been estimated that there will be well more than 500,000 hip fractures a year in the United States.5 Hip fractures frequently result in a decline in functional status and a need for assistance with activities of daily living. This associated decline in function frequently results in loss of independence and requires up to 20% of patients previously living independently to move to long-term care facilities for at least a year after their fracture.6–8 The direct and indirect costs for the individual, their family and the taxpayer are staggering and will only increase.6 The Centers for Disease Control has estimated that by 2020 the annual direct and indirect cost of injuries related to falls will reach nearly $55 billion in 2007 dollars.9 Therefore, hip fractures will continue to be a challenge for patients and their families, healthcare providers and policy makers. THE HIP FRACTURE SYNDROME: THE INTERACTION OF BONE AND FALL-RELATED FACTORS Hip fractures occur when a force directed to the proximal femur exceeds the elastic properties of the bone. In osteoporosis research and clinical care, hip fracture prevention has largely focused on identifying patients with low bone mass and instituting therapies to increase bone density to improve bone strength. Accumulated fatigue damage, bone microarchitecture and mineralization10 also contribute to bone quality and strength but are not clinically measured. Although low bone density is a known risk factor for hip fracture, it has less ability to predict fractures than other nonbone risk factors.11 In addition, the efficacy of bone-active agents in reducing hip fractures is also limited with absolute risk reductions commonly at 1% or a number-needed-to-treat (NNT) value of 100. Furthermore, their effectiveness in reducing risk of hip fracture in patients older than 80 years is not established.12 More recently, in an attempt to predict individual patient fracture risk to guide pharmacologic treatment decisions, models that include risk factors for hip fracture other than bone density have been developed. The World Health Organization Fracture Risk Assessment Tool (FRAX) index has been promoted as a means to assess risk with or without bone density measurements.13 The FRAX algorithm incorporates 10 clinical risk factors [age, sex, body mass index, previous fracture, family history of fracture, glucocorticoid use, current smoker, alcohol use of 3 units/d or more, rheumatoid arthritis and hip bone mineral density (BMD) T-score if available] and generates a 10-year risk of fracture. Treatment recommendations vary depending on which management guidelines are used14 Recently, the U.S. Preventive Services Task Force noted that there are simpler tools, such as age and BMD or age and fracture history that predict hip fractures as well as the FRAX.15–18 Because more than 90% of hip fractures occur after a fall,19–21 strategies to lower fall risk are fundamental to reduce hip fractures. Interventions that rely solely on improving bone density or increasing bone strength will have only a modest effect. A shift in the clinical (and research) paradigm is required to better address the etiology, evaluation and management of hip fracture risk (Figure 1). From the Department of Internal Medicine, Section of Geriatrics, University of Texas Southwestern Medical Center, Dallas, Texas. Submitted January 6, 2011; accepted in revised form January 14, 2011. This review was supported in part by the Margaret and Trammell Crow Distinguished Chair in Alzheimer’s and Geriatric Research and the Murrell Geriatric Research Fund. Correspondence: Craig D. Rubin, MD, Department of Internal Medicine, Section of Geriatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX (E-mail: craig.rubin@ utsouthwestern.edu).