A new look at fracture risk assessment scores
Gourlay ML, Overman RA, Fine JP, et al; Women's Health Initiative Investigators. Time to clinically relevant fracture risk scores in postmenopausal women. Am J Med. 2017;130:862.e15-e23.
Jiang X, Gruner M, Trémollieres F, et al. Diagnostic accuracy of FRAX in predicting the 10-year risk of osteoporotic fractures using the USA treatment thresholds: a systematic review and meta-analysis. Bone. 2017;99:20-25.
The FRAX score has become a popular form of triage for women who do not yet meet the bone mass criteria of osteoporosis. Current practice guidelines recommend use of fracture risk scores for screening and pharmacologic therapeutic decision making. Some newer data, however, may give rise to questions about its utility, especially in younger women.
Fracture risk analysis in a large postmenopausal population
Gourlay and colleagues conducted a retrospective competing risk analysis of new occurrence of treatment-level and screening-level fracture risk scores. Study participants were postmenopausal women aged 50 years and older who had not previously received pharmacologic treatment and had not had a first hip or clinical vertebral facture.
Details of the study
In 54,280 postmenopausal women aged 50 to 64 years who did not have a bone mineral density test, the time for 10% to develop a treatment-level FRAX score could not be estimated accurately because the incidence of treatment-level scores was rare.
A total of 6,096 women had FRAX scores calculated with bone mineral density testing. In this group, the estimated unadjusted time to treatment-level FRAX scores was 7.6 years (95% CI, 6.6-8.7) for those aged 65 to 69, and 5.1 years (95% CI, 3.5-7.5) for women aged 75 to 79 at baseline.
Of 17,967 women aged 50 to 64 who had a screening-level FRAX at baseline, 100 (0.6%) experienced a hip or clinical vertebral fracture by age 65 years.
Age is key factor. Gourlay and colleagues concluded that postmenopausal women who had subthreshold fracture risk scores at baseline would be unlikely to develop a treatment-level FRAX score between ages 50 and 64. The increased incidence of treatment-level fracture risk scores, osteoporosis, and major osteoporotic fracture after age 65, however, supports more frequent consideration of FRAX assessment and bone mineral density testing.
Related article:
2015 Update on osteoporosis
Meta-analysis of FRAX tool accuracy
In another study, Jiang and colleagues conducted a systematic review and meta-analysis to determine how the FRAX score performed in predicting the 10-year risk of major osteoporotic fractures and hip fractures. The investigators used the US treatment thresholds.
Details of the study
Seven studies (n = 57,027) were analyzed to assess the diagnostic accuracy of FRAX in predicting major osteoporotic fractures; 20% was used as the 10-year fracture risk threshold for intervention. The mean sensitivity and specificity, along with their 95% CIs, were 10.25% (3.76%-25.06%) and 97.02% (91.17%-99.03%), respectively.
For hip fracture prediction, 6 studies (n = 50,944) were analyzed, and 3% was used as the 10-year fracture risk threshold. The mean sensitivity and specificity, along with their 95% CIs, were 45.70% (24.88%-68.13%) and 84.70% (76.41%-90.44%), respectively.
Predictive value of FRAX. The authors concluded that, using the 10-year intervention thresholds of 20% for major osteoporotic fracture and 3% for hip fracture, FRAX performed better in identifying individuals who will not have a major osteoporotic fracture or hip fracture within 10 years than in identifying those who will experience a fracture. A substantial number of those who developed fractures, especially major osteoporotic fracture within 10 years of follow up, were missed by the baseline FRAX assessment.
WHAT THIS EVIDENCE MEANS FOR PRACTICE
Increasing age is still arguably among the most important factors for decreasing bone health. Older women are more likely to develop treatment-level FRAX scores more quickly than younger women. In addition, the FRAX tool is better in predicting which women will not develop a fracture in the next 10 years than in predicting those who will experience a fracture.
Increasing age is still arguably among the most important factors for decreasing bone health. Older women are more likely to develop treatment-level FRAX scores more quickly than younger women. In addition, the FRAX tool is better in predicting which women will not develop a fracture in the next 10 years than in predicting those who will experience a fracture.
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