An optimal intervention threshold of FRAX in postmenopausal Thai women

This study was designed to determine a FRAX intervention threshold in postmenopausal Thais, based on a history of hip fracture. The optimal FRAX thresholds for hip fracture were 4.9% (without BMD) and 4% (with BMD), while the thresholds for major osteoporotic fracture were 9.8% (without BMD) and 8.9% (with BMD).

Fracture Risk Assessment Tool (FRAX) has been widely used as an intervention threshold for initiating osteoporosis treatment. However, there is a lack of data to validate the threshold in Thai population.

A cross-sectional study was conducted from January 2014 to February 2019. Postmenopausal women in the Northeast of Thailand whom has bone mineral density (BMD) measured using dual-energy X-ray absorptiometry (DXA) in the study period were recruited. Participants who had previously received anti-osteoporotic treatment were not eligible. FRAX score, both with and without BMD, was calculated using a Thai reference. Prevalent hip fracture was identified by reviewing the ICD-10 diagnosis from the hospital database during the study period. The receiver operating characteristic (ROC) curve and Youden index were used to determine the FRAX threshold in predicting hip fracture, based on the rationale that women with a prevalent hip fracture would be eligible for treatment.

A total of 2872 postmenopausal Thai women were recruited, with 45 sustained a recent hip fracture. In association with hip fracture, the optimal FRAX thresholds for hip fracture without and with BMD were 4.9% and 4%, respectively, with 71.1% sensitivity and 83.3% specificity, and 82.2% sensitivity and 78.6% specificity, while the optimal FRAX thresholds for major osteoporotic fracture (MOF) without and with BMD were 9.8% and 8.9%, respectively, with 75.6% sensitivity and 77.0% specificity, and 86.7% sensitivity and 70.9% specificity.

An optimal intervention threshold based on FRAX of hip fracture and MOF in postmenopausal Thai women is slightly different from the standard recommendation, which confirmed the marked variations of thresholds across ethnicities. The proposed threshold should be considered as new cutoff for initiating osteoporosis treatment in postmenopausal Thais.