SCREENING FOR OSTEOPOROSIS IN CROHNS-DISEASE - A DETAILED EVALUATION OF CALCANEAL ULTRASOUND

Objectives To compare calcaneal broadband ultrasonic attenuation (BUA) and velocity of sound (VOS) in patients with Crohn's disease with an age-matched control population. The validity of BUA as a screening too l for osteoporosis was evaluated and the relationship between BUA and previous fracture studied. Design Cross-sectional study. Background Si nce patients with Crohn's disease are at risk of osteoporosis and prem ature fracture, routine assessment of bone mineral density (BMD) is re commended. Quantitative ultrasound of the calcaneum is an inexpensive and radiation-free means of assessing bone density which also provides information on bone microstructure. Methods BUA (dB/MHz) and VOS (m/s ) were measured at the calcaneum (CUBAclinical, McCue Ultrasonics, Win chester, UK) and compared with bone mineral density at the hip and lum bar spine measured by dual-energy X-ray absorptiometry (DEXA); 100 pat ients (42 men) with Crohn's disease and 52 age-matched healthy control s (23 men) were studied. Results BUA was significantly reduced in pati ents with Crohn's disease compared with age-matched controls [76.53 dB /MHz (+/- 17.3) vs 87.29 dB/MHz (+/- 17.9), difference in means = 10.7 6, 95% CI -16.67, -4.85, P = 0.0004] and was significantly associated with BMD at the spine (r = 0.49, 95% CI 0.32, 0.63, P < 0.0001) and fe moral neck (r = 0.54, 95% CI 0.38, 0.67, P < 0.0001). In the diagnosis of osteoporosis (t score < -2.5) BUA had a sensitivity of 66.7% at th e femoral neck, with a specificity of 85.6%; sensitivity of BUA at the spine was 75% with specificity 89%. Conclusion Patients with Crohn's disease have reduced BUA compared with an age-matched control populati on. Calcaneal BUA is significantly associated with BMD at the hip and spine but the correlation is insufficient to recommend ultrasound as a screening tool for DEXA. (C) 1998 Rapid Science Ltd.