Infliximab, osteoporosis and osteopoenia in Crohn’s disease

Abstract

Introduction: Osteoporosis is common among Crohn’s disease patients. Aims and methods: The aim of our study was to establish which factors are associated with a greater risk of osteoporosis in Crohn’s disease. 83 Crohn’s disease patients were recruited. Informed consent was obtained to gather their phenotypic data in a database and perform a DEXA scan. Results: Mean patient age was 39 years with mean disease duration of 9 years. Mean Z score spine: -0.4, Z score hip: -0.7, T score spine: -0.7, T score hip: -1.3. 30% of the population had osteopoenia and 6% had osteoporosis at the spine. 46% had osteopoenia and 14% had osteoporosis at the hip. Factors which were associated with lower DEXA scores were young age of disease onset (ANOVA p=0.024), patients on Infliximab (p=0.005), long-term steroid use (p=0.032) and low body mass index (BMI, p=0.004). Disease location (ANOVA p=0.851), disease behavior (p=0.911) smoking (p=0.181) and increasing age(>50 years) (p=0.128) were not associated with low DEXA scores. Conclusions: Low BMI, early disease onset and longterm steroid use are risk factors for osteoporosis in Crohn’s disease. An important risk factor for low bone density is Infliximab. Lower Z scores in patients on Infliximab may occur as these patients have more severe inflammation, requiring aggressive treatment. Turk N et al1 have shown that in Crohn’s patients, the proinflammatory cytokine TNF-α is associated with the osteoclastogenic receptor activator of NFKB-ligand, and inversely with bone density. A second explanation might be that low bone densities in patients on Infliximab are a side-effect of the drug. There is no data to suggest this. Studies2-3 show Infliximab to have a beneficial effect on bone turnover markers in Crohn’s patients in the short term. Randomly controlled long-term trials are needed to evaluate the impact of Infliximab on bone density.