BOSTON — There has been little consensus among organizational guidelines in the past 5 years about who should be screened for low bone density.
Recommendations range from very conservative to relatively liberal, said Edward Leib, M.D., director of the Osteoporosis Center at the University of Vermont, during a recent symposium on bone health sponsored by Boston University School of Medicine.
The decision to screen is important, since it can affect a patient's well-being and dictates how the health care system allocates billions of dollars.
For many clinicians, the decision is understandably murky. Evidence that bone scans prevent fractures is conflicting, and there is some evidence that screening may indirectly cause harm.
Screening guidelines issued by various organizations answer some questions and raise others. For instance, in 2002, the U.S. Preventive Services Task Force (USPSTF) published letter grade recommendations on osteoporosis screening after reviewing the literature on its diagnosis and treatment. Its evidence-based screening recommendations are among the most conservative to date, said Dr. Leib.
The Task Force noted that bone density screening is an imprecise science, and its accuracy and usefulness is dependent on variable technical and human factors.
Bone density scans lack meaningful predictive value, the Task Force also noted. They don't predict who will and who will not have a fracture. Moreover, if a test is positive, it is unclear what a clinician should do.
“There is little evidence regarding which patients are likely to benefit from screening and treatment,” the Task Force concluded. “It is not known whether women who have a similar overall risk for fracture, but different bone densities, will benefit similarly from treatment. This is clinically important because the lack of accepted criteria for initiating treatment remains a problem.”
The USPSTF also noted that there are several potential harms of screening, although “the empirical data for them are few.”
The Task Force said potential harms from screening include an increased likelihood that a patient will need to receive hormone replacement therapy; increased patient fears and anxiety; inaccuracies and misinterpretations of bone density tests; increased risk for ulcer disease in patients taking alendronate (incidence 2.2% on alendronate vs. 1.2% on placebo); and unknown long-term harms of alendronate.
After considering all of these factors, the USPSTF recommended screening women aged 65 years and older, and women aged 60 years and older who have risk factors for osteoporosis.
The Task Force found insufficient evidence to recommend for or against routine screening in women aged 60 years and younger, or in women aged 60–64 years who are not at increased risk for osteoporotic fractures.
Bone densitometry screening guidelines generally agree that women aged 65 years and older should undergo bone density scans. But what do the guidelines say about younger women, men, and children? Researchers have yet to validate the reliability of screening guidelines in these groups (N. Engl. J. Med. 2005;353:164–71).
The current guidelines suggest that clinicians should take into account a number of risk factors before ordering bone densitometry for them. In women younger than 65, clinicians should consider fragility or low-trauma fracture, family history, and weight, among other things.
Dr. Leib said that his advice on osteoporosis screening is based on evidence and opinion. He recommends bone densitometry for the following individuals: women aged 65 years and older and men aged 70 years or older; postmenopausal women with risk factors for fracture; men aged 50 years or older with risk factors; routine screening of early postmenopausal women; and premenopasual women, children, or younger men with significant risk factors.
Dr. Leib is a consultant to Procter & Gamble and Merck Pharmaceuticals. He receives research support from Eli Lilly and NPS Allelix.