Background A low bone quality is a risk factor for fractures, independent of the bone mineral density (BMD). Pentosidine and homocysteine are the main bone quality markers used in the clinical situation, and the levels of these markers are reported to be high in patients with rheumatoid arthritis (RA) compared to normal controls. It has been shown that biologics and methotrexate reduce the serum pentosidine level. However, there have so far been no reports that have compared the homocysteine level, bone metabolic markers and bone mineral density after treatment with biologics.
Objectives The aim of this study was to assess the expression of bone quality markers, bone metabolic markers, BMD and disease activity in patients with RA who were receiving biologics and to compare these values to those in patients who were not.
Methods Sixty-two RA patients (nine male, 53 female; median age: 66.5 years) without diabetes or renal dysfunction were included in this study. Thirty-two of the 62 patients received biologics (six patients received infliximab, seven etanercept, five adalimumab, 10 tocilizumab, two abatacept and two golimumab). Eighteen patients were receiving oral bisphosphonates, nine were receiving raloxifene and two were receiving alfacalcidol. The plasma concentrations of pentosidine, homocysteine, intact P1NP, TRACP-5b, CRP, ESR, and the MMP-3 levels, as well as the DAS28-ESR, DAS28-CRP, CDAI and SDAI scores, and the BMD (lumbar spine and proximal femur) were assessed. We compared these parameters between patients being treated with biologics (B group) and those being treated with other agents (N group). The relationships between disease activity and bone quality markers were also examined.
Results The DAS28-ESR, DAS28-CRP, CDAI and SDAI scores were significantly lower in the biologics group than the non-biologics group (p<0.05). The BMD (lumbar spine and proximal femur), intact P1NP, TRACP-5b and homocysteine levels showed no significant differences between the two groups. However, the level of pentosidine was significantly lower in the biologics group than in the non-biologics group (p<0.05). The pentosidine level was significantly correlated with the disease activity, particularly with the CDAI (R=0.421, P<0.01) and SDAI (R=0.426, P<0.01) scores. The homocysteine level was significantly correlated with the DAS28-CRP, but there was no significant correlation between the pentosidine and homocysteine levels.
Conclusions In this study, the BMD and bone metabolic markers showed no significant differences between the patients being treated with biologics and those who were not. However, the level of pentosidine was significantly lower in the biologics group. These results suggest that biologics can improve not only the disease activity, but also the bone quality, via a homocysteine-independent pathway.
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Kageyama Y, Takahashi M, Nagafusa T, et al; Etanercept reduces the oxidative stress marker levels in patients with rheumatoid arthritis. Rheumatol Int. 2008; 28: 245-251.
Disclosure of Interest None Declared