Application of the WHO fracture risk assessment tool (FRAX) to predict need for DEXA scanning and treatment in patients with inflammatory bowel disease at risk of osteoporosis

P>Background Although patients with inflammatory bowel disease (IBD) are at increased risk of osteoporosis, low bone mineral density (BMD) alone confers only a modest increase in risk of fracture. The FRAX score, developed by the WHO, is a free web-based clinical scale assessing the 10-year fracture risk and need for lifestyle advice/reassurance, dual X-ray absorptiometry (DEXA) scanning or preventive treatment. Aim To assess the accuracy of pre-BMD FRAX scores in identifying at risk IBD patients needing BMD measurement (intermediate risk) and/or therapy (high risk). Methods We calculated FRAX scores retrospectively in 116 consecutive IBD out-patients (81 Crohn's disease, 35 ulcerative colitis), who were having DEXA scans in 2005-2009 because they were considered at risk of osteoporosis. Results On DEXA scans, 47% (38/81) and 12% (10/81) patients with Crohn's disease were osteopaenic and osteoporotic, respectively; equivalent figures for patients with UC were 34% (12/35) and 14% (5/35). The clinical FRAX score alone, when compared with the FRAX score including the BMD result, had a sensitivity of 100% (95% CI: 70-100%), specificity of 40% (95% CI: 31-50%), positive predictive value of 16% (95% CI: 9-27%) and negative predictive value of 100% (95% CI: 90-100%) in identifying those patients needing BMD measurement (intermediate risk) or preventive therapy (high risk). Conclusions In patients with IBD perceived to be at risk of osteoporosis and/or osteopaenia, the clinical FRAX score alone can predict accurately the risk of osteoporotic fracture, and thereby reduce the need for DEXA scans and unnecessary anti-osteoporosis treatment.