Can peripheral DXA measurements be used to predict fractures in elderly women living in the community?

Abstract

While axial dual energy X-ray absorptiometry (DXA) is the accepted ‘gold standard’ method both for diagnosing osteoporosis and predicting fractures, appropriate equipment is not universally available. Peripheral bone mass measurements may have the potential to identify patients at risk of fracture and to be used to target appropriate treatment. We assessed the effectiveness of peripheral DXA (PIXI, GELunar) in the assessment of risk and targeting treatment to prevent future fracture in 7,604 women aged 60–80 from five centres across Britain. At enrolment women completed a lifestyle and risk factor questionnaire and had a PIXI DXA scan of the heel. Women were categorised by PIXI DXA bone mineral density (BMD) into high, medium or low risk of future osteoporotic fracture. Treatment was recommended to those at highest risk. Follow-up was by simple questionnaire 18–24 months after baseline assessment. Seventy-four percent returned the follow-up questionnaire. The area under the receiver operator characteristic (ROC) curves for any fracture and osteoporotic fracture were comparable to those published using other sites and technologies. A 1-SD decrease in PIXI BMD was associated with an 86% increase in risk of osteoporotic fracture. Of the women identified as high risk, 74% had started treatment following their heel scan and 84.7% continued to take treatment at follow-up. No significant difference was noted in fracture rates in those who started treatment after assessment compared to those who did not. While peripheral DXA is highly effective for predicting older women who are at increased risk of future fracture, it has yet to be established as an effective method for targeting bisphosphonate or other therapy.