FRAX analysis

Published Date: 19th July 2016

Publication Authors: Tayal V, Abernethy R, Clewes A, Dawson J, O'Rourke T

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Background 

Bone health is a significant problem with over 300,000 patients presenting with fragility fractures to hospitals in the UK each year resulting in 20% mortality and 50% disability. FRAX and Q fracture are two fracture risk-assessment tools available to use in the UK.

FRAX is an important tool to assess 10-year fracture risk by using clinical risk factors in clinic and to determine the need for bone densitometry measurement (DXA).1 Moreover, refinement of this risk requires reassessment with bone mineral density (BMD).

Objectives  

We undertook an analysis of our annual-review clinics osteoporosis assessment data to evaluate whether addition of BMD to FRAX improves the risk assessment for fragility fractures and results in reclassification from a low-risk to high-risk and vice-versa.

Methods 

50 patients with established Rheumatoid Arthritis (those patients with obvious rheumatoid deformities) who attended the annual-review clinics at our District general Hospital in the North-West of UK from Feb 2011 to Jan 2012 were included in the study. All patients had a DXA scan as part of annual review. Patients previously on bisphosphonate treatment were excluded. Data collected included age, sex, weight, BMI, history of previous fragility fracture or parent hip fracture, current steroid treatment, smoking, alcohol intake (more than 3 units a day), secondary osteoporosis and femoral-neck absolute BMD (or femoral-neck T-score where absolute value not available). FRAX was calculated on all patients with and without BMD.

Results 

22 (44%) patients were below intervention threshold on FRAX calculation on clinical factors alone (before BMD). After adding BMD to FRAX, none of these patients needed treatment. As per NOGG guidelines, 5 (10%) patients classified as requiring bone protection treatment without BMD. After adding BMD to FRAX, 8 patients (16%) classified as requiring treatment. 7 (14%) patients reclassified from low to high-risk (requiring treatment) and 3 (6%) reclassified from high to low-risk (not requiring treatment). Mean femoral-neck BMD in patients reclassifying to high risk was 0.60 gm/cm2 compared to 0.718 gm/cm2 in patients reclassifying to low risk. Adding BMD to FRAX calculation therefore reclassified risk in 10 (20%) patients. A minimum risk-score value of 17% for a major osteoporotic fracture (pre-DEXA) had a 60% predictive value for a need for definitive treatment post DEXA scan.

Conclusions 

Despite its inadequacies, FRAX remains an important tool to evaluate fracture-risk to patients. Adding BMD to FRAX calculation could lead to reclassifying risk in a significant proportion of patients especially if the risk is near threshold values and identifies patients for treatment who would have been otherwise missed. However, larger studies are needed to evaluate the net clinical benefit of adding BMD to FRAX

Tayal, V; Nair, JR; Abernethy, R; Dawson, J; Clewes, A; O'Rourke, T. (2013).  Does addition of bone mineral density to FRAX analysis help reclassify fracture risk?  Annals of the Rheumatic Diseases. 72 (Suppl 3), A303

 

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