The University of Alabama at Birmingham CERT Seeks To Reduce Disparities in Hip Fracture Trends and Rates

By Shelley Norden Barnes

As more and more Baby Boomers reach retirement age, the declining rate of hip and other osteoporotic fractures in the United States should be great news. And it is…if you’re an older white woman. For older nonwhites, however, the news is not as good. While overall osteoporosis-related fracture rates have steadily dropped among whites since 1995, the rates for African Americans, Hispanics, and Asian Americans have not dropped as sharply. This discrepancy was recently studied by epidemiologist Nicole Wright, Ph.D., a member of the University of Alabama Deep South Arthritis and Musculoskeletal Center for Education and Research on Therapeutics (UAB CERT).

"The risk factors for osteoporosis and hip fractures are, generally, being female, white or Asian and having a small stature, yet [these factors] may not describe all populations, particularly with regard to some minority groups," says Wright, whose research has focused on osteoporosis for nearly a decade. "I wanted to know if [every group] was declining at the same rate or if there were negative trends in a particular group that would warrant more intervention."

To begin to answer these questions, Wright and her colleagues at the UAB CERT embarked on a series of studies to examine a standard risk-prediction tool, fracture patterns, and fracture trends in racial and ethnic subgroups to determine if there are population-based variations.

"Our CERT focuses on arthritis and musculoskeletal conditions in the Deep South, so looking at disparities related to musculoskeletal disease fits into our theme, especially with physicians such as Kenneth Saag and Jeffrey Curtis, both renowned researchers who have investigated disparities before," Wright explains.

The FRAX Prediction Tool: Does One Size Really Fit All?

Under the direction of Saag, who is principal investigator for the UAB CERT, Wright and fellow researchers evaluated studies that used the World Health Organization standard fracture risk assessment (FRAX^®) tool² to predict the likelihood of fractures in various populations. The current FRAX tool uses age, gender, personal and parental history of fractures, medical history, and lifestyle factors to develop a 10-year likelihood of having a major osteoporotic fracture. While the FRAX tool has been useful in overall epidemiological studies, researchers have questioned its effectiveness in predicting fracture risk in specific subpopulations.

In their research, Wright and Saag reviewed studies in which the FRAX tool either overestimated or underestimated fracture risk in select subpopulations. Their findings of published studies reported last year in Current Rheumatology Reports,¹ are noteworthy:

• The FRAX tool accurately predicts fracture risk in women with normal to low bone mass, but it underestimates fracture risk in women with borderline osteoporosis and low bone mass and, therefore, may be too conservative for use in this subpopulation.
• Type 2 diabetes increases the risk of fracture and has been proposed as an independent fracture risk factor that should be incorporated into the FRAX tool; particularly in people younger than 65 years of age, as it was shown that younger adults with either type 1 or type 2 diabetes have more than five times the risk of hip fracture when compared with people in that age group without diabetes.
• The FRAX tool does not perform as well in subpopulations that differ from those who participated in the original FRAX validation study, and its scores cannot be extrapolated to observation times other than 10 years.

Based on the results of this study, UAB CERT researchers concluded that the FRAX methodology needs to be modified to include additional variables so it can be useful in evaluating the risk of fractures in subpopulations.

"Changes to the FRAX tool have the potential not only to help target risk in a broader range of patients but also to aid in prevention efforts," Wright explains. "For example, if patients have low bone mass but not at the critical level of osteoporosis, they may not receive treatment based on that one factor. But if risk factors such as diabetes and falls were added to the FRAX model—and a patient has those risk factors as well—the prevalence of those three together may increase that patient’s overall FRAX score enough to justify starting treatment."

The Role of Race in Hip Fracture Rates

Wright and her UAB CERT colleagues also conducted a cohort study to investigate hip fracture incidence trends among racial/ethnic subgroups of older Medicare beneficiaries. The study, published last year in the Journal of Bone and Mineral Research³ found that overall hip fracture incidence decreased by 8 percent in men and by 14 percent in women between 2000 and 2009. However, the trends varied by race/ethnicity and age. For example, while modest decreases were found among white, African American, and Asian Medicare beneficiaries, there was little evidence of change among Hispanics. This situation could have a considerable negative impact on U.S. public health, given that the number of Hispanics aged 65 years and older is projected to increase by 200 percent, as opposed to only 60 percent among non-Hispanic whites in the next two decades.

"The overall declines in hip fracture rates mean that treatments are working, but at a public health level, we may need to focus a bit more on the Hispanic population in particular since it’s at higher risk," Wright suggests. Her hope is that these findings may encourage clinicians to evaluate the research more closely and identify some new risk factors, such as diabetes, that may be more prevalent in these higher risk groups.

 "Diabetes has been shown to have a very high risk for fracture, and it is more prevalent in African American and Hispanic populations," Wright explains. Based on their findings, the UAB CERT researchers have concluded that the field needs more targeted prevention efforts to lower the risk of hip fractures in the aging population, which is projected to increase by 80 percent by 2030, and the potentially negative impact those fractures would have on the growing Hispanic population.

Turning Disparities Into Dialogue

Ultimately, Wright wants to correct these disparities on a patient-by-patient basis, with clinicians evaluating patients individually rather than according to any subpopulation to which they belong.

"It’s important that clinicians not classify people or avoid engaging in key conversations because they assume, for example, that [an overweight] black female patient isn’t at risk for osteoporosis," Wright explains. "While African Americans may have the lowest incidence of fractures, particularly of the hip, they have the highest 1-year mortality after a fracture." For this reason, Wright believes that all comorbidities should be considered in relation to musculoskeletal disease and that populations traditionally thought not to be at risk for facture should receive attention.

For the short term, Wright is striving to build awareness so that patients and physicians can begin a dialogue about the possibility of potential risks for osteoporotic fracture.

"Other health conditions are trumping bone health, and while it’s important to maintain blood pressure and control your cholesterol, it is also important to maintain bone health as someone with osteoporosis may have to deal with it for 40 or more years," Wright explains. "We need to bring more awareness to minority groups, particularly in Hispanic and Black populations. We need more awareness on fracture rates and the "newer" fracture risk factors, so that if they have a one of those conditions, say diabetes, they can initiate a conversation with their doctor about their bone health."

References

1. Wright NC, Saag KG. From fracture risk prediction to evaluating fracture patterns: recent advances in the epidemiology of osteoporosis. Curr Rheumatol Rep. 2012 Jun;14(3):206-11. PMID: 22453874.
2. World Health Organization. FRAX^®: Fracture Risk Assessment Tool. http://www.shef.ac.uk/FRAX/. Accessed June 27, 2013.
3. Wright NC, Saag KG, Curtis JR, et al. Recent trends in hip fracture rates by race/ethnicity among older U.S. adults. J Bone Miner Res. 2012 Nov;27(11):2325-32. PMID: 22692958.

The University of Alabama at Birmingham Deep South Arthritis and Musculoskeletal Center for Education and Research on Therapeutics is one of six nationwide CERTs funded by the Agency for Healthcare Research and Quality. The mission of each CERT is to conduct research and provide education that will advance the optimal use of drugs, medical devices, and biological products; increase awareness of the benefits and risks of therapeutics; and improve quality while cutting the costs of health care.