A nomogram for predicting osteoporosis risk based on age, weight and quantitative ultrasound measurement.

INTRODUCTION: Quantitative ultrasound measurement (QUS) or clinical risk index alone are not reliable tools for the identification of women with osteoporosis. This study examined the prognostic value of combined QUS and clinical risk index for predicting osteoporosis risk in Thai women.
METHODS: The study was designed as a cross-sectional investigation with 300 women of Thai background, aged between 38 and 85 years (mean age: 58). Femoral neck bone mineral density (BMD) was measured by DXA (Hologic QDR-4500; Bedford, MA, USA). A femoral neck BMD T-scores <or= -2.5 was defined as "osteoporosis"; otherwise, "non-osteoporosis". QUS was measured by Achilles+ (GE Lunar, Madison, WI, USA) and converted to T-score. Three models for predicting osteoporosis were considered: model I included age, weight and QUS, model II included age and weight, and model III included only QUS. The prognostic performance among the models was assessed by the area under the receiver operating characteristic curve (AUC).
RESULTS: The prevalence of osteoporosis was 12.7% (n=38/300) by femoral neck BMD. Age, weight and QUS were each significantly associated with osteoporosis risk. The AUC+/-SE value for model I was 0.86 +/- 0.03, which was significantly higher (p=0.02) than that for model II (AUC = 0.80 +/- 0.04) or model III (AUC = 0.79 +/- 0.04). Based on the estimated parameters of model I, a nomogram was constructed for predicting osteoporosis.
CONCLUSION: These data suggest that the combination of QUS and age and weight could significantly improve the prognosis of osteoporosis in Asian women, and that the nomogram can assist primary care physicians in the identification of high-risk women.