US Preventative Services Task Force FRAX threshold has a low sensitivity to detect osteoporosis in women ages 50-64 years

Abstract

The US Preventative Services Task Force (USPSTF) recommends consideration for screening for osteoporosis in women under age 65 who have an estimated 10-year major osteoporotic fracture risk of 9.3 % or higher. We found that this threshold for osteoporosis screening in women ages 50-64 years old has a low sensitivity to detect osteoporosis.

Introduction: The US Preventative Services Task Force (USPSTF) recommends consideration of dual-energy X-ray absorptiometry (DXA) in women under ages 50-64 with a major osteoporotic fracture (MOF) risk of 9.3 % or higher, as estimated by the fracture risk assessment tool (FRAX) tool. We assessed the performance of the 9.3 % MOF risk threshold for detecting osteoporosis and evaluated whether DXA indication appeared appropriate, based on USPSTF criteria and other risk factors, at our institution.

Methods: We performed a retrospective record review of women ages 50-64.5 years old to determine clinical factors and FRAX scores of women undergoing a DXA at our institution over a 6-month period after the USPSTF recommendations were released and evaluated the sensitivity and specificity of the 9.3 % MOF threshold to detect densitometric osteoporosis. Additionally, using the USPSTF criteria and several additional risk factors, we evaluated the extent of potentially inappropriate DXA use in women ages 50 to 64 years in a large primary care practice in an academic medical center.

Results: The analysis included 465 DXA tests. The overall sensitivity and specificity of a FRAX-calculated MOF risk ≥9.3 % was 37 and 74 %, respectively, for the detection of osteoporosis. The receiver operator characteristic curve (ROC) demonstrated an area under the curve of 0.58. Lowering the FRAX risk threshold to 5.5 % would increase the sensitivity of detecting osteoporosis in our population from 37 to 80 % while reducing the specificity from 74 to 27 %. Out of 465 DXAs, 371 (79.8 %) were classified as appropriately ordered per our pre-specified criteria. Of the 120 women with osteoporosis at the hip and/or spine based on T-score values of -2.5 or less, 14 DXAs (11.7 %) were classified as potentially inappropriate based on a FRAX-predicted MOF risk less than 9.3 % and lack of additional pre-specified risk factors.

Conclusion: We found that the USPSTF-recommended MOF risk threshold of 9.3 % for osteoporosis screening in women ages 50-64 years old has a low sensitivity to detect osteoporosis.