Screening for Postmenopausal Osteoporosis: Latest Guidelines

In the United States, osteoporosis affects 12% to 28% of women over age 65 years. Among women who live to be 85, 50% will sustain an osteoporosis-related fracture. Hip fractures occur in 15% of these women, and vertebral deformities develop in 25%.¹

In elderly women, hip fractures are associated with high mortality and loss of independence. Vertebral fractures (Figure) not only cause extreme pain, but also result in 150,000 hospital admissions and 161,000 office visits per year.¹

How best to identify patients at greatest risk before fractures occur? The answer can be found in new guidelines on osteoporosis screening from the US Preventive Ser-vices Task Force (USPSTF).^1,2 Highlights of these guidelines follow. (The full text is available at: www.preventiveservices.ahrq.gov.)

WHOM TO SCREENWomen aged 65 and older. The USPSTF recommends routine osteoporosis screening for all women aged 65 and older. This recommendation is based on good evidence that the incidence of osteoporosis and related fractures increases steadily with age.

Regular screening and subsequent treatment of newly diagnosed osteoporosis in asymptomatic women over age 65 reduces the risk of fracture. In women aged 65 to 69, 1 hip fracture could be prevented for every 731 women screened (Table).

Women aged 60 to 64. The incidence of osteoporosis in women aged 60 to 64 (6.5%) is less than that in older women (12% and higher with increasing age). Therefore, the USPSTF determined that general screening for low-risk women in this age group is not effective. In the 60- to 64-year-old age group, 1856 women would need to undergo screening in order to prevent just 1 hip fracture.

However, the USPSTF does recommend selective screening for a subgroup of women aged 60 to 64 who are at high risk for osteoporosis and related fractures. High-risk women under the age of 65 are identified by 3 criteria (known as the Osteoporosis Risk Assessment Instrument):

• Age of 60 to 64 years.
• Lower body weight (less than 70 kg [154 lb]).
• No current use of estrogen.

The other risk factors studied (smoking, weight loss, family history, decreased physical activity, alcohol or caffeine use, and low calcium and vitamin D intake) were not supported by enough evidence to include in the screening guidelines.

WHICH TEST- AND HOW OFTEN?
To determine which screening test is most effective, the USPSTF reviewed various methods of measuring bone density. Dual-energy x-ray absorptiometry (DEXA) at the femoral neck is the best predictor of hip fracture; it is equivalent to forearm measurements in assessing the risk of fracture at other sites.

New research indicates that peripheral bone density testing may determine which women are at higher risk for fracture in the short term (1 year).³ More studies are needed to compare the accuracy of DEXA with that of peripheral bone density testing.

The optimal interval for osteoporosis screening remains undetermined because there is no research to support a recommendation. However, because of limitations in the precision of testing, a minimum of 2 years between screenings is necessary to accurately measure a change in bone mineral density (BMD). Thus, 2-year intervals may be appropriate for older women, and less frequent testing (eg, every 5 years) may suffice for younger postmenopausal women. Repeated screening is more likely to detect osteoporosis in older women, those with lower BMD at baseline, and those with other fracture risk factors. In view of the lack of available data in women over the age of 85, the USPSTF has not recommended an appropriate age at which to discontinue screening.

POTENTIAL HARMS OF SCREENING
Screening for osteoporosis poses several potential harms. One study found that women who received a diagnosis of osteoporosis experienced increased fear and anxiety as a result of perceived vulnerability.⁴ In addition, inaccuracies in bone density testing and misinterpretation of results may lead to inappropriate or inadequate treatment.

References:

REFERENCES:1. Nelson HD, Helfand M, Woolf SH, Allan JD.Screening for postmenopausal osteoporosis: areview of the evidence for the US Preventive ServicesTask Force. Ann Intern Med. 2002;137:529-541.
2. US Preventive Services Task Force. Screening forosteoporosis in postmenopausal women: recommendationsand rationale. Ann Intern Med. 2002;137:526-528.
3. Siris ES, Miller PD, Barrett-Connor E, et al. Identificationand fracture outcomes of undiagnosed lowbone mineral density in postmenopausal women: resultsfrom the National Osteoporosis Risk Assessment.JAMA. 2001;286:2815-2822.
4. Lyles KW, Gold DT, Shipp KM, et al. Associationof osteoporotic vertebral compression fractures withimpaired functional status. Am J Med. 1993;94:595-601.