Ultrasound measurements of calcaneus for estimation of skeletal status in patients with inflammatory bowel disease

Background: Patients with inflammatory bowel disease (IBD) are at risk of d eveloping metabolic bone disease. In diagnosing osteoporosis,bone mineral d ensity (BMD) measurements play a key role. Our aims in this study were to a ssess the skeletal status with quantitative ultrasound (QUS) and to evaluat e the ability of this method to predict BMD as measured by dual-energy X-ra y absorptiometry (DXA) in IBD patients. Methods: Altogether 53 patients wit h Crohn disease (CD) and 57 with ulcerative colitis (UC) were studied by us ing a Lunar Achilles ultrasound bone densitometer. The ultrasound variables are broadband ultrasound attenuation (BUA)and speed of sound (SOS). The lu mbar spine, femoral neck, and total body BMD were measured with DXA. The ag e- and sex-adjusted values (Z-scores) were obtained by comparison with age- and sex-matched normal values. Results: In CD patients Z-scores for both B UA and SOS were significantly less than zero, and Z-score for SOS was signi ficantly lower than that for UC patients. Z-scores for BMD measured with DX A were significantly lower at all measurements In patients with CD. QUS and DXA measurements were significantly correlated. However, the agreement bet ween the measurements in each individual patient was poor. Body mass index (BMI) was a major determinant for both BUA and SOS. In CD patients low QUS variables were associated with corticosteroid therapy, and both CD and UC p atients with previous fractures had low SOS values. Conclusions: Our study indicates that QUS and DXA are not interchangeable methods for estimation o f bone status. QUS variables are insufficient to provide accurate predictio n of BMD values and should therefore not be recommended as a screening test for osteoporosis in IBD patients.