Analysis of Bone Quality in Adult Patients With Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is considered a risk factor for the development of osteoporosis, which leads to an increased risk of fractures. There is no data on bone quality obtained with imaging techniques other than bone densitometry such as Trabecular Bone Score (TBS), 3D bone densitometry (DXA-3D) or quantitative bone ultrasound (QUS).

HYPOTHESES OF THE STUDY Subjects with inflammatory bowel disease present an alteration in bone quality that can be assessed by TBS, with TBS values expected to be lower than those of subjects without IBD or known bone pathology, with a decrease of up to 50 points in this parameter.

Primary Objective : to evaluate and compare the values of the trabecular bone score (TBS), a surrogate marker of bone quality, in patients with inflammatory bowel disease (IBD) and in a control group of volunteers without IBD or known metabolic bone pathology, recruited in the consultations of the Endocrinology and Nutrition, Digestive System and Rheumatology departments of the Hospital Ruber Juan Bravo during routine health control visits, adjusted for age, sex and body mass index (BMI).

Secondary Objectives

1. To compare bone mineral density (BMD) values measured by dual energy X-ray absorptiometry (DXA) at the lumbar spine (anteroposterior and lateral) and proximal femur in patients with IBD with those of a control group of subjects adjusted for age, sex and BMI.
2. To compare the ultrasound velocity and attenuation parameters (BUA and SOS) obtained by quantitative ultrasound of the calcaneus (QUS) in patients with IBD with those of a control group of subjects adjusted for age, sex and BMI.
3. To analyse the prevalence and severity of vertebral fractures using the Vertebral Fracture Assessment (VFA) software of lateral DXA in patients with IBD compared to a control group adjusted for age, sex and BMI.
4. To correlate the TBS results with the ultrasound velocity and attenuation parameters (BUA and SOS) obtained with QUS.
5. To correlate TBS results with BMD parameters measured by DXA in the lumbar spine (anteroposterior and lateral) and in the proximal femur.
6. To compare biochemical markers of bone remodelling [carboxy-terminal telopeptide of type I collagen (ß-CTx Crosslaps) and N-terminal propeptide of type I protocolagen (P1NP)] in patients with IBD with a control group of subjects adjusted for age, sex and BMI.
7. To correlate baseline levels of biochemical markers of bone remodelling with the results of: a) BMD obtained with DXA in the lumbar spine (anteroposterior and lateral) and in the proximal femur, b) TBS values and c) parameters obtained with QUS.
8. To assess the absolute 10-year risk of major fractures and hip fractures using the FRAX tool, in subjects with IBD. To correlate the absolute risk of fractures with the TBS and QUS values.
9. To evaluate the effect of adjusting the FRAX tool by including TBS values for the calculation of the absolute risk of major and hip fractures.
10. To analyse the evolution of bone microarchitecture parameters measured by TBS, bone ultrasound parameters of ultrasound velocity and attenuation, BMD in the lumbar spine (anteroposterior and lateral) and in the proximal femur and biochemical markers of bone remodelling in patients with IBD after one year of follow-up.
11. To analyse the discriminative capacity for the diagnosis of vertebral fractures evaluated with VFA of the TBS and QUS values, compared with the BMD values obtained in lumbar DXA (anteroposterior and lateral) in patients with IBD.
12. To compare volumetric BMD parameters measured by 3D bone densitometry (DXA-3D) of the hip in patients with IBD with a control group of subjects adjusted for age, sex and BMI.
13. To correlate bone quality parameters measured by TBS and QUS with volumetric BMD measured by 3D DXA-3D in the hip.
14. To evaluate the effect of the different disease-modifying treatments (biologicals, corticoids, etc.) on TBS values, bone ultrasound parameters, BMD values by conventional DXA and DXA-3D in patients with IBD.

This study is organised into two sub-studies:

• Sub-study 1: observational, analytical, prospective, cross-sectional. Cohort-type study, with a cohort of patients with IBD and a cohort of volunteers without IBD or known metabolic bone pathology, recruited in the consultations of the Endocrinology and Nutrition, Digestive System and Rheumatology departments of the Ruber Juan Bravo Hospital during routine health control visits, adjusted for age, sex and body mass index (BMI). The baseline data on bone quality measured by: a) bone densitometry in the lumbar spine (anteroposterior and lateral), b) bone densitometry in the proximal femur, c) TBS, d) DEXA-3D, e) calcaneal ultrasound, e) fractures assessed by VFA and f) biochemical markers of bone remodelling in both cohorts will be analysed to respond to the primary objective, secondary objectives 2 to 9 and exploratory objectives 11 to 14.
• Sub-study 2: observational, analytical, prospective and longitudinal, with one-year follow-up of IBD patients only. Bone quality parameters measured by: a) bone densitometry in the lumbar spine (anteroposterior and lateral), b) bone densitometry in the proximal femur, c) TBS, d) DEXA-3D, e) calcaneal ultrasound, e) fractures assessed by VFA and f) biochemical markers of bone remodelling will be analysed to respond to secondary objective 10.