Changes in Bone Turnover Assessed in Rituximab-Treated Rheumatoid Arthritis
The effects of rituximab on BMD was influenced by vitamin D status, gender, menopausal status, and changes in disease activity.
In patients with rheumatoid arthritis (RA), bone mineral density (BMD) is maintained at the lumbar spine and forearm, but decreases in the femur after treatment with rituximab, according to results published in PLoS ONE.
The study included participants with RA who were followed for a 12-month period (n=36). The researchers assessed changes in BMD, bone turnover, inflammation, and disease activity before and after treatment with rituximab.
After treatment with rituximab, participants showed significant reductions in inflammatory markers (C-reactive protein [CRP] median change, −3.7 mg/L; 95% CI, −10.3 to 0.7 mg/L; P =.014; erythrocyte sedimentation rate median change, −8 mm/hr; 95% CI, −19.0 to 1.0 mm/hr; P =.006) and disease activity (28-joint Disease Activity Score based on CRP median change, −0.84; 95% CI, −1.64 to −0.41; P <.001).
After 12 months, the researchers did not find significant changes in lumbar spine BMD. However, they did find significant reductions in neck of femur BMD (mean difference, −0.017 g/cm2; 95% CI, −0.030 to −0.004 g/cm2; P =.011) and total femur BMD (mean difference, −0.016 g/cm2; 95% CI, −0.025 to −0.007; P =.001).
The researchers found significant increases in procollagen type 1 N-terminal propeptide (median change from baseline to 12 months, 11.3 μg/L; 95% CI, −1.1 to 24.8 μg/L; P =.025) and bone-specific alkaline phosphatase (median change from baseline to 12 months, 2.5 μg/L; 95% CI, 1.2-3.6 μg/L; P =.002).
"The effects of rituximab on BMD seems to be influenced by vitamin D status, gender, menopausal status, changes in disease activity and could also be confounded by the requirement for prednisolone," the researchers wrote. "A larger study powered to take into account all these factors is required and this will necessitate that vitamin D insufficiency or deficiency be corrected from the start."
Wheater G, Elshahaly M, Naraghi K, et al. Changes in bone density and bone turnover in patients with rheumatoid arthritis treated with rituximab, results from an exploratory, prospective study. PLoS ONE. 2018;13(8):e0201527.