Application of FRAX Model to Sri Lankan Postmenopausal Women

Abstract 

The FRAX software developed by the World Health Organization provides a method to estimate fracture probability of old men and women based on their bone mineral density (BMD) and clinical risk factors (CRFs). The validity of 4 selected ethnic-specific FRAX tools in determining prevalent fracture or treatment decisions in a group of postmenopausal women from Sri Lanka was examined. Women with a history of fragility fracture/s and those who were detected to have femoral neck T-score<2.5 were considered eligible for specific osteoporosis treatment. Ten-year all osteoporotic fracture (vertebral and nonvertebral) probability (10y-AOFP) of 481 postmenopausal women were estimated on US Caucasian, US Asian, Japanese, and Chinese FRAX tools, first using CRFs alone and then combining with femoral neck T-scores. At 20% 10y-AOFP, Chinese tool showed a very low sensitivity in detecting prevalent fracture or detecting women needing intervention (1.3%). Sensitivities observed with US Asian and Japanese tools ranged from 33% to 42%, showing their limitations in predicting prevalent fracture in this group of women. The US Caucasian tool, either with CRFs alone or with BMD incorporated, showed a relatively higher sensitivity in detecting fractures or identifying those needing interventions (71% and 76%, respectively). Furthermore, the US Caucasian tool showed a relatively high specificity (ranging from 70% to 87%). In conclusion, this analysis showed the limitations of the current FRAX tools in predicting fractures when applied to a different ethnic group. Until a separate FRAX tool is developed, the US Caucasian tool can be used to predict fractures in Sri Lankan postmenopausal women.

Key Words: FRAX, Osteoporosis, Sri Lanka