Patients with Crohn's disease (CD) develop similar rates of osteoporosis, osteopenia, and normal bone density whether or not they are treated with TNF-alpha inhibitors, a new study published in the Scandinavian Journal of Gastroenterology report.
Numerous studies have documented a high incidence of vitamin D deficiency, osteoporosis, and bone fractures in CD patients, and various inflammatory cytokines, including TNF-alpha, have been linked to increased bone resorption. Few studies, however, have evaluated the impact of anti-TNF medications on osteoporosis and fracture risk in CD patients.
The research team led by Dr. Shahrad Hakimian from UMass Memorial Medical Center, reviewed data on 464 patients with CD. Average vitamin D levels were similar, albeit low, in the TNF treatment group (19.9 ng / mL) and in the TNF-treatment-naive group (20.9 ng / mL). The two groups also did not differ in their rates of vitamin D deficiency, insufficiency, and normal vitamin D levels.
Bone density scans in 168 patients showed similar rates of osteoporosis, osteopenia, and normal bone density between the TNF treatment group (100 patients) and the treatment-naive group (68 patients).
Osteoporosis rates for patients under age 60 were higher for those using TNF-alpha inhibitors than for nonusers (15.4% vs. 3.6%); osteoporosis rates between patients 60 or older were lower with TNF treatment (18.2%) than with nonuse (30.0%).
Few patients (9% of the TNF group and 16% of the treatment-naive group) had any type of fracture. Among the patients who had fractures, their average age at fracture was 47 years in the TNF group versus 61 years in the treatment-naive group.
"Further large prospective studies comparing bone density before and after initiation of anti-TNF medications may be useful in addressing some of the confounders present in the current study," the researchers conclude. "It is important to recognize and treat osteoporosis and vitamin D deficiency in this patient population to minimize this risk."
Dr. Francisco Augusto Sylvester from University of North Carolina, Chapel Hill, said, "The study is provocative, as it suggests that anti-TNF agents are associated with worse bone health in adults with Crohn's disease. However, I don't think that this study definitively shows that the anti-TNF agents per se are responsible for worse bone mass in patients with Crohn's disease. Their main result may be biased due to confounding by association.”
“In this study, patients with Crohn's disease with more severe disease received anti-TNF agents (as evidenced by more frequent complicated disease and admissions to hospital),” he explained. “Therefore, it is quite possible that the more severe Crohn's disease is responsible for worse bone health and not the anti-TNF agent."
“In children, prospective studies have shown a significant improvement in bone health on anti-TNF agents,” Sylvester added. “Therefore, I agree with the authors that properly designed prospective studies are needed to settle the question about the effects of anti-TNF therapy on bone in adults.”