Clinical, biochemical, and densitometric profiles and FRAX risk calculations of South African patients with fragility fractures of the hip: observations from a tertiary care centre

Abstract

Purpose: Although fragility hip fractures (HF) in the South African (SA) population are among the lowest worldwide, the incidence of HF is  expected to more than double over the next few decades. Little is known about the contributors to increased hip fracture risk,  including low bone mineral density (BMD), in our unique population. In addition, the ability of the recently calibrated SA Fracture Risk  Assessment Tool (FRAX) to identify high fracture risk in the SA population accurately has not been validated.

Methods: A retrospective, descriptive, cohort study of SA postmenopausal women and men ≥ 50 years who presented with fragility HFs  was conducted. The ability of clinical risk factors (CRFs) and BMD measured by dual-energy X-ray absorptiometry (DXA), as well as  calculated FRAX probability scores, to identify the known high fracture risk in SA patients were evaluated. The SA FRAX tool was used, and  a high fracture risk defined if the United States (US) fixed thresholds for major osteoporotic (MOF) and/or HF risk were exceeded (≥ 20%  and ≥ 3% over 10 years respectively). 

Results: A total of 163 patients were included. The most useful predictive CRFs were age and  gender, recreational toxins in men, and a history of falls. Most were females (71%), who were older than males. DXA-BMD and FRAX-HF  calculations best identified the known high fracture risk in the study cohort. FRAX-MOF calculations performed poorly. 

Conclusion:  Fracture risk assessment tools did not identify the known high fracture risk in all of the elderly study cohort with HF. Clinicians must  continue to appreciate the important role of a good clinical assessment to ensure optimal fracture risk prediction.