Usefulness of FRAX tool for the management of osteoporosis in the Spanish female population

Background and objective: Osteoporotic fractures involve a significant consumption of health resources. Bone densitometry has been essential in the management of osteoporosis. However, for fracture absolute risk prediction, other important clinical risk factors are also important. WHO published a risk estimation tool (FRAX), and the National Osteoporosis Guideline Group (NOGG) reported thresholds for densitometry assessment based on cost-effectivity criteria. Our goal is to determine the diagnostic predictive validity of FRAX in our population, and to assess how its use (according to NOGG guidelines) would modify the current number of referrals to DXA scan in our health system. Subjects and methods: Diagnostic validation study in a consecutive sample of 1,650 women, 50 to 90 years old, under no treatment with anti-resortives, from the FRIDEX cohort. DXA and a questionnaire regarding risk factors were performed. ROC curve and area under the curve (AUC) were used to assess FRAX's diagnostic validity for femoral neck osteoporosis (FNOP). Risk of fracture was calculated using FRAX pre and postDXA, and women were classified according to their risk, following NOGG recommendations. Results: FRAX's ROC AUC for FNOP was 0.812 for major fracture and 0.832 for hip fracture. Using FRAX according to NOGG would result in performing only 25.2% of the current tests. If we added previous fracture antecedent to the algorithm, 49.4% of the tests performed would be advised. Conclusions: The use of NOGG thresholds applied to FRAX would reduce about 50% the current number of referrals to DXA scan in our population. FRAX has a good diagnostic validity for FNOP. (C) 2010 Elsevier Espana, S.L. All rights reserved.