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Development and application of a Japanese model of the WHO fracture risk assessment tool (FRAX).

Fujiwara S, Nakamura T, Orimo H, Hosoi T, Gorai I, Oden A, Johansson H, Kanis JA - Osteoporos Int (2008)

Bottom Line: There were small differences in T-scores between those used for the model and those derived from a Japanese reference population.The approach will need to be supported by appropriate health economic analyses.However, when applying the FRAX model to Japan, T-scores and Z-scores should be converted to those derived from the international reference.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Studies, Radiation Effects Research Foundation, Hiroshima, Japan. fujiwara@rerf.or.jp

ABSTRACT

Unlabelled: The present study estimated the 10-year probability using the Japanese version of WHO fracture risk assessment tool (FRAX) in order to determine fracture probabilities that correspond to intervention thresholds currently used in Japan and to resolve some issues for its use in Japan.

Introduction: The objective of the present study was to evaluate a Japanese version of the WHO fracture risk assessment (FRAX) tool to compute 10-year probabilities of osteoporotic fracture in Japanese men and women. Since lumbar spine bone mineral density (BMD) is used preferentially as a site for assessment, and densitometers use Japanese reference data, a second aim was to investigate the suitability and impact of this practice in Japan.

Methods: Fracture probabilities were computed from published data on the fracture and death hazards in Japan. Probabilities took account of age, sex, the presence of clinical risk factors and femoral neck BMD. Fracture probabilities were determined that were equivalent to intervention thresholds currently used in Japan. The difference between T-scores derived from international reference data and that using Japanese-specific normal ranges was estimated from published sources. The gradient of risk of BMD for fracture in Japan was compared to that for BMD at the lumbar spine in the Hiroshima cohort.

Results: The 10-year probabilities of a major osteoporosis-related fracture that corresponded to current intervention thresholds ranged from approximately 5% at the age of 50 years to more than 20% at the age of 80 years. The use of femoral neck BMD predicts fracture as well as or better than BMD tests at the lumbar spine. There were small differences in T-scores between those used for the model and those derived from a Japanese reference population.

Conclusions: The FRAX mark tool has been used to determine possible thresholds for therapeutic intervention, based on equivalence of risk with current guidelines. The approach will need to be supported by appropriate health economic analyses. Femoral neck BMD is suitable for the prediction of fracture risk among Japanese. However, when applying the FRAX model to Japan, T-scores and Z-scores should be converted to those derived from the international reference.

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Related in: MedlinePlus

Correlation between 10-year fracture probabilities (%) in women without clinical risk factors computed from normative data using NHANES III reference values and Japanese-derived reference values for femoral neck BMD. BMI is set at 23.4 kg/m2
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Fig4: Correlation between 10-year fracture probabilities (%) in women without clinical risk factors computed from normative data using NHANES III reference values and Japanese-derived reference values for femoral neck BMD. BMI is set at 23.4 kg/m2

Mentions: The reference mean in women aged 20–29 years at the femoral neck was 0.858 g/cm2 (SD = 0.120 g/cm2) using the NHANES III data. When young normal values were computed from the Japanese population the mean BMD was 0.786 g/cm2 (SD = 0.107 g/cm2). Thus the threshold for osteoporosis using the NHANES III data was 0.558 g/cm2 and that derived from the Japanese data was 0.519 g/cm2. The thresholds for osteopenia (WHO definition) were 0.738 g/cm2 and 0.679 g/cm2, respectively. Thus there were systematic differences in the T-score derived from the two data sets. A comparison of fracture probabilities computed from the z-scores using the two approaches is shown in Fig. 4 for different combinations of risk factors. The differences in probabilities were relatively modest, but as expected, the use of Japanese reference values overestimated fracture probabilities.Fig. 4


Development and application of a Japanese model of the WHO fracture risk assessment tool (FRAX).

Fujiwara S, Nakamura T, Orimo H, Hosoi T, Gorai I, Oden A, Johansson H, Kanis JA - Osteoporos Int (2008)

Correlation between 10-year fracture probabilities (%) in women without clinical risk factors computed from normative data using NHANES III reference values and Japanese-derived reference values for femoral neck BMD. BMI is set at 23.4 kg/m2
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2267486&req=5

Fig4: Correlation between 10-year fracture probabilities (%) in women without clinical risk factors computed from normative data using NHANES III reference values and Japanese-derived reference values for femoral neck BMD. BMI is set at 23.4 kg/m2
Mentions: The reference mean in women aged 20–29 years at the femoral neck was 0.858 g/cm2 (SD = 0.120 g/cm2) using the NHANES III data. When young normal values were computed from the Japanese population the mean BMD was 0.786 g/cm2 (SD = 0.107 g/cm2). Thus the threshold for osteoporosis using the NHANES III data was 0.558 g/cm2 and that derived from the Japanese data was 0.519 g/cm2. The thresholds for osteopenia (WHO definition) were 0.738 g/cm2 and 0.679 g/cm2, respectively. Thus there were systematic differences in the T-score derived from the two data sets. A comparison of fracture probabilities computed from the z-scores using the two approaches is shown in Fig. 4 for different combinations of risk factors. The differences in probabilities were relatively modest, but as expected, the use of Japanese reference values overestimated fracture probabilities.Fig. 4

Bottom Line: There were small differences in T-scores between those used for the model and those derived from a Japanese reference population.The approach will need to be supported by appropriate health economic analyses.However, when applying the FRAX model to Japan, T-scores and Z-scores should be converted to those derived from the international reference.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Studies, Radiation Effects Research Foundation, Hiroshima, Japan. fujiwara@rerf.or.jp

ABSTRACT

Unlabelled: The present study estimated the 10-year probability using the Japanese version of WHO fracture risk assessment tool (FRAX) in order to determine fracture probabilities that correspond to intervention thresholds currently used in Japan and to resolve some issues for its use in Japan.

Introduction: The objective of the present study was to evaluate a Japanese version of the WHO fracture risk assessment (FRAX) tool to compute 10-year probabilities of osteoporotic fracture in Japanese men and women. Since lumbar spine bone mineral density (BMD) is used preferentially as a site for assessment, and densitometers use Japanese reference data, a second aim was to investigate the suitability and impact of this practice in Japan.

Methods: Fracture probabilities were computed from published data on the fracture and death hazards in Japan. Probabilities took account of age, sex, the presence of clinical risk factors and femoral neck BMD. Fracture probabilities were determined that were equivalent to intervention thresholds currently used in Japan. The difference between T-scores derived from international reference data and that using Japanese-specific normal ranges was estimated from published sources. The gradient of risk of BMD for fracture in Japan was compared to that for BMD at the lumbar spine in the Hiroshima cohort.

Results: The 10-year probabilities of a major osteoporosis-related fracture that corresponded to current intervention thresholds ranged from approximately 5% at the age of 50 years to more than 20% at the age of 80 years. The use of femoral neck BMD predicts fracture as well as or better than BMD tests at the lumbar spine. There were small differences in T-scores between those used for the model and those derived from a Japanese reference population.

Conclusions: The FRAX mark tool has been used to determine possible thresholds for therapeutic intervention, based on equivalence of risk with current guidelines. The approach will need to be supported by appropriate health economic analyses. Femoral neck BMD is suitable for the prediction of fracture risk among Japanese. However, when applying the FRAX model to Japan, T-scores and Z-scores should be converted to those derived from the international reference.

Show MeSH
Related in: MedlinePlus