Biological/targeted synthetic DMARDs do not arrest bone loss in patients with rheumatoid arthritis: a multicenter prospective observational study

Objective To elucidate the differential effects of biological/target synthesized DMARDs (b/tsDMARDs) on bone metabolism in patients with rheumatoid arthritis (RA) in a real-world cohort.Methods This was a multicentre prospective observational study of RA patients enrolled at the time of first b/tsDMARDs administration. Bone mineral density (BMD) and bone turnover markers (BTMs) were measured during the 52-week observation. The study was designed to enrol all eligible RA patients. The end-points were differences in changes in BMD according to b/tsDMARD type, and the correlation between BMD and BTMs.Results A total of 1164 patients were enrolled in this study. b/tsDMARDs improved RA disease activity from mean CDAI 25.5 at baseline to 4.5 at week 26. Patients not receiving anti-osteoporotic agents (anti-OP) at baseline with no history of fracture experienced a significant decrease in both femoral neck (F: mean 0.666-0.655 g/cm3) and radial (R: 0.518-0.514) BMD at week 26. Despite maintaining low CDAI levels during weeks 26-52 (5.3-4.4), there was a continued decline in BMD (F: 0.653, R: 0.509. Weeks 52). None of the b/tsDMARDs type preserved BMD. Conversely, patients receiving anti-OP at baseline maintained stable BMD throughout the study (Weeks 0/26/52. F: 0.551/0.551/0.555, R: 0.415/0.416/0.415). Although BTMs were changed by b/tsDMARDs, the changes were unrelated to those in BMD.Conclusion Our study suggested the progression of osteoporosis in RA patients during b/tsDMARDs treatment without anti-OP. BTMs may not reflect BMD change. Regular monitoring of BMD in RA should be considered for early management of osteoporosis. Graphical Abstract

Automated summary

This study aimed to investigate the effects of biological/target synthesized DMARDs (b/tsDMARDs) on bone metabolism in patients with rheumatoid arthritis (RA). The results showed that without anti-osteoporotic treatment, b/tsDMARDs treatment could lead to the progression of osteoporosis in RA patients. Bone turnover markers (BTMs) may not be able to reflect changes in bone mineral density (BMD). Therefore, regular monitoring of BMD in RA patients is recommended for early management of osteoporosis.