FRAX - Fracture Risk Assessment in Osteoporosis

Author: Cathy R. Kessenich, DSN, ARNP, Professor and Nurse Practitioner

University of Tampa
Department of Nursing
401 W. Kennedy Blvd
Tampa, FL 33606

Telephone: (813) 257-3160
Fax: (813) 258-7214
Email: ckessenich@ut.edu

Introduction

Osteoporosis is a chronic, debilitating disease that represents a major worldwide health problem. The medical and economic impact of this disease is increasing as society ages and identification of osteoporosis improves. Osteoporosis is typically silent until a fracture occurs. Osteoporotic fractures are due to low bone mass even when they result from a considerable fall or trauma. Fractures due to osteoporosis may be followed by a complete recovery or more commonly chronic pain and anxiety about a subsequent fracture. Mortality may be increased following both hip and vertebral fractures.

Early identification of patients at risk for fractures due to osteoporosis is crucial in order to begin therapy that may reduce fracture risk. Because the disease is silent until a fracture occurs, patients are frequently undiagnosed and untreated until very late in the disease process. The World Health Organization (WHO) fracture prediction algorithm (abbreviated FRAX) was recently developed to assist practitioners in determining patient’s absolute risk of a major osteoporotic fracture within 10 years. The computer model allows an assessment of the likelihood of hip or other major osteoporosis-related fracture for individual patients.¹ Several international studies have provided evidence that the FRAX model enhances the assessment of osteoporotic fracture risk in both men and women.^2,3

There are numerous categories of drugs used to treat osteoporosis and prevent fractures. The most commonly prescribed of these are oral bisphosphonates. Currently there are daily, weekly, and monthly varieties of these drugs. Oral bisphosphonates must be taken in a very specific manner to be effective. Additionally, since osteoporosis is typically silent, many patients choose not to fill initial prescriptions and/or not to refill them. It has been well documented that many patients are not adherent to prescribed bisphosphonate therapy and this lack of adherence leads to an increased risk of osteoporotic fractures.^4,5 The FRAX model will be a useful tool in educating patients about their risk of osteoporotic fractures within 10 years and may help in adherence to prescribed therapies.

The FRAX model

The FRAX model is available through the National Osteoporosis Foundation website (www.nof.org) or at www.shef.ac.uk/FRAX/. (see Table 1) It is intended to be used in the clinical setting to help providers make treatment decisions and to educate patients about their personal risk of osteoporotic fracture within ten years. It is anticipated that it will soon be available as a software update for dual energy x-ray absorptiometry (DXA) machines that measure BMD. For those providers who do not have internet access in the office setting, paper charts may be downloaded that describe the 10 year probability of a major osteoporotic fracture when either BMD or body mass index (BMI) is known. (see Table 2). The FRAX model predicts the risk of a major osteoporotic fracture within ten years and can be compared to the Framingham model for prediction of cardiovascular events and the Gail model for prediction of breast cancer. The FRAX, Framingham and Gail models serve to inform providers and patients about the probability of major illness events and should be used by providers to make treatment decisions and patients to make personal health choices.

After many years of investigation the WHO task force chose to include several risk factors in the FRAX model. They are: current age, gender, personal history of a fracture, femoral neck BMD, low body mass index, use or oral glucocorticoid therapy, secondary osteoporosis (e.g. rheumatoid arthritis), parental history of hip fracture, current smoking, and alcohol intake of 3 or more drinks/day.⁶ This model can be applied only to previously untreated patients. It predicts absolute fracture risk which is the calculation of the 10-year probability of a hip fracture or other major osteoporotic fracture factoring in BMD and clinical risk factors.

Benefits of FRAX

Osteoporosis may be diagnosed and treated by specialists such as endocrinologists and/or rheumatologists. However, more commonly it is addressed primary care settings. Nurses working in primary care settings may or may not have particular expertise in osteoporosis identification and management. Additionally, primary care nurses typically have much less time with patients and a greater variety of acute and chronic diseases to manage than specialists. In a recent study of clinical practitioners in Canada both expert and non-expert clinicians were provided FRAX data on patients for whom a BMD test was requested. The non-expert clinicians in the study strongly preferred receiving FRAX data to traditional BMD results only.⁷ FRAX may help to save time and provide useful direction to practitioners who are not experienced in osteoporosis management.

Limitations of FRAX

The current FRAX model provides a good foundation for clinical decision making and will certainly evolve over time. Currently it does not include spinal BMD or bone turnover markers. These bone marker data are not available from many of the countries that contributed to the information to develop FRAX. The FRAX model does not include data on BMD measured at peripheral skeletal sites. Most of the patient data included in the development of the model were derived from women only and data on ethnic groups prevalent in the United States in limited. The FRAX model cannot be used in patients who have been treated with osteoporosis medications because the probability of fracture may be overestimated. For some patients, a 10 year probability may be too long a time frame to consider. The current FRAX model provides an analysis of fracture risk with and without BMD, but will most certainly evolve as it is applied and refined for future use.

Conclusions

Historically, providers made treatment decisions solely on BMD and an individual clinical assessment of the patients need for therapy. Patients made therapeutic choices based on their comprehension of the disease and its implications. The FRAX model will assist in more informed decision making by both providers and patients. The concept of absolute risk assessment and the FRAX model have been supported by the International Osteoporosis Foundation (IOF) and the National Osteoporosis Foundation (NOF). Both organizations strongly advocate the use of FRAX in clinical decision making. Nurses involved in the identification and treatment of patients with osteoporosis should be aware of this risk assessment model and evaluate its application to their practice.

References

1. Siris, E, Delmas PD. Assessment of 10-year absolute fracture risk: a new paradigm with worldwide application. (2008) Osteoporos Int 19:383-384.
   
   
2. Kanis JA, Johnell O, Oden A, Johansson H, McCloskey E. (2008). FRAX and the assessment of fracture probability in men and women from the UK. Osteoporos Int 19: 385-97.
   
   
3. Fujiwara S, Nakamura T, Orimo H, et al. (2008) Development and application of a Japanes model of the WHO fracture risk assessment tool (FRAX). Osteoporos Int 19:429-35.
   
   
4. Penning-van FJA, Erkens JA, Olson M, Herings RMC. (2008) Loss of treatment benefit due to low compliance with bisphosphonate therapy. Osteoporosis Int 19:511-517.
   
   
5. Siris Es, Harris ST, Rosen CJ et al. (2006) Adherence to bisphosphonate therapy and fracture rates in osteoporotic women: relationship to vertebral and nonvertebral fractures from 2 US claims databases. May Clin Proc 81: 1013-1022.
   
   
6. National Osteoporosis Foundation. Clinician’s guide to prevention and treatment of osteoporosis, National Osteoporosis Foundation, Washington, DC, pp. 10, 2008.

Table 1 FRAX online tool located at www.shef.ac.uk/FRAX/

Table 2 FRAX Paper charts available for download via the website.