Use trabecular bone score also to evaluate bone health in all IBD patients

A European study has suggested trabecular bone score (TBS) helps to assess bone quality in patients with active inflammatory bowel disease (IBD) and provides more useful information about bone health.

A cross-sectional study was conducted in 81 patients with inflammatory bowel disease to evaluate bone quality as well as bone quantity. A similar number of individuals without IBD or any other metabolic bone disease formed the control group. Bone quality was measured by TBS, while bone mineral density (BMD) determined bone quantity. The Harvey–Bradshaw Index (HBI) for Crohns disease and the Partial Mayo Score for ulcerative colitis were used to clinically assess disease activity.

The lumbar spine BMD was lower in patients with IBD in comparison to the control group; 1.06 ± 0.18 vs. 1.16 ± 0.15 g/cm2, p < 0.005, respectively. Likewise, the hip BMD and TBS were lower in IBD patients; 0.88 ± 0.13 vs. 0.97 ± 0.13 g/cm2 and 1.38 ± 0.1 vs. 1.43 ± 0.1, respectively. Both TBS (1.32 ± 0.13 vs. 1.40 ± 0.9, p = 0.03) and lumbar spine BMD (0.92 ± 0.19 vs. 1.07 ± 0.1, p = 0.01) were lower in patients with stricturing phenotype of Crohn’s disease versus non-stricturing Crohn’s disease suggesting that the inflammatory process of Crohn’s disease also affects the bones. HBI score was found to be an independent predictor of low TBS in patients with Crohn’s disease indicating that the disease per se was also a contributory factor in osteoporotic changes.

Since steroids are the most common cause of secondary osteoporosis and steroids are used to treat IBD, the study also analysed the impact of high dose steroids on BMD. Patients with no history of steroid intake or those who had taken only a single course of steroid treatment had higher BMD at the lumbar spine (1.14 ± 0.01 vs. 0.95 ± 0.01 g/cm², p = 0.001) and hip (0.95 ± 0.03 vs. 0.82 ± 0.03 g/cm², p = 0.02) and TBS (1.42 ± 0.02 vs. 1.31 ± 0.03, p = 0.005) compared to patients who had taken more than four courses of steroid treatment. However, only the TBS was statistically decreased in patients with multiple courses of steroids as compared with patients who had taken 2 to 4 courses of steroids (1.31 ± 0.03 vs. 1.39 ± 0.02, p = 0.012).

BMD is often decreased in IBD patients predisposing them to osteoporotic “fragility” fractures. Factors contributing to low BMD include the chronic inflammatory nature of the disease, malabsorption and use of steroids.

BMD is the gold standard test for osteoporosis, but it only provides information regarding the quantity of bone. Bone strength is not synonymous with BMD. Bone quality i.e., the bone composition and structure. also influences bone strength and must be taken into consideration when assessing fracture risk. Evaluation of all IBD patients, particularly those on high-dose steroids, must include TBS for early detection of osteoporotic changes. This study further establishes that low TBS correlates with increased disease activity. Hence, achieving disease remission will improve both bone density and bone quality and reduce fracture risk.

Reference

Soare I, et al. Assessment of bone quality with trabecular bone score in patients with inflammatory bowel disease. Sci Rep. 2021 Oct 13;11(1):20345.