Background It is well-known that patients with chronic inflammatory diseases have more bone loss and a higher risk of fractures compared to general population. The causes of bone loss in inflammatory disorders are multiple. Recent studies suggest that inflammation in RA is a main contributor. Use of medications associated with osteoporosis and physical inactivity may play an important role too. On the other side anti TNFα therapy can control inflammation and may have a positive effect on bone health.
Objectives To examine the effect of anti-TNF α blockers on bone mineral density and bone turnover in patients with severe, active rheumatoid arthritis (RA).
Methods The 12-month prospective study enrolled 48 patients (36 postmenopausal women, 12 men, mean age 56.2 years, range 47–68 years,) with severe, active rheumatoid arthritis (DAS 28 score above 5.1) and decreased bone mineral density (BMD was in osteopenic range according to WHO classification). In all patients anti TNF treatment was initiated (adalimumab 22, etanercept 17 and certolizumab pegol 9 pts.). None of the patients was on antiporotic treatment (except calcium and vitamin D) and patients with changes in corticosteroid, use more than ±2,5mg of prednisolon, were not enrolled. BMD measurements of the total hip and lumbar spine were performed using dual-energy X-ray absorptiometry before the treatment and 12 months after the treatment. Bone turnover markers (BTM) osteocalcin (OC) and C-terminal telopeptide of collagen type I (CTx) were evaluated at the same time.
Results BMD changes at the femoral neck and lumbar spine between baseline and 12 months after treatment were not statistically significant (0.896±0.124g/cm 2 versus 0.890±0.133 g/cm2 and 0,978±0.139g/cm2 vs 0,986±0.145g/cm2 respectively), but a trend for BMD increase (+1.0%) at the lumbar spine was observed. Significant increase (P <0.001) in osteocalcin levels (mean 21,124±7,10 before treatment and 27,35±8,17 after the treatment) and significant decrease (P <0.001) of CTx (438,40±188 vs 330,93±142,11) was observed. Paired Student's t-test was used for statistical analysis.
Conclusions Our findings suggest that anti-TNF therapy may have a positive (uncoupling) effect on bone turnover markers and maintain stable BMD in such a high risk group of patients with severe RA. Stable dose of prednisolone during the study diminished the influence of corticosteroids on final results. Long-term use of TNF α blockers in RA might be therefore associated with an increase in bone strength, and fractures reduction. Properly controlled long-term trials are needed to fully evaluate the supposed antifracture efficacy of TNF blockade.
Disclosure of Interest None declared