Osteoimmunology in rheumatoid arthritis: a comparison between conventional therapies and biologics

Abstract Background Rheumatoid arthritis is an immune-mediated disease that affects the peripheral joints and is characterized by chronic systemic inflammation with systemic bone mineral density loss. Susceptibility to osteoporosis occurs due to systemic inflammation, as well as chronic corticosteroid use. The biologic and target-specific disease-modifying antirheumatic drugs (DMARDs) act effectively blocking systemic inflammation. We hypothesized that patients receiving biologic and target-specific DMARDs have higher bone mineral density, exhibit lower serum pro-inflammatory cytokine levels, and require lower corticosteroid doses than those receiving conventional therapy. Methods To test this hypothesis, we conducted a quantitative, descriptive, observational, cross-sectional and prospective clinical trial by collecting data from eligible patients. The participants were divided into three groups according to DMARD class (conventional synthetic, biologic, and target-specific DMARDs). The main inflammatory mediators of osteoporosis secondary to rheumatoid arthritis (tumor necrosis factor-α, interleukin-6), Disease Activity Score in 28 Joints, calculated using C-reactive protein, bone mineral density, bone turnover biomarker C-terminal telopeptide, and glucocorticoid dose were assessed in the three groups. Analysis of variance and Pearson product-moment correlation coefficient were used to compare the results among groups. Trial Registration Number - Certificate of Presentation for Ethical Consideration (CAAE): 46069821.4.0000.8667, 07/15/2021. Results TNF-α and IL-6 levels did not show significant correlation with any variable, such as DAS28-CRP, CTX, and bone mineral density of the lumbar spine, total femur, and femoral neck. The prednisone dose was significantly positively correlated with CTX and DAS28-CRP. Conclusion Among patients with Rheumatoid arthritis treatment with any disease-modifying antirheumatic drugs achieving low disease activity or remission decrease circulating cytokine levels and low bone resorption.