The impact of biological therapy on bone in rheumatoid arthritis after three years: data from the Moroccan RBSMR registry

Author(s): Laila Taoubane1*, Abdellah El Maghraoui2, Abderrahim majjad1, Najlae El Ouardi1, Hamza taoufik1, Ihsan Hmamouchi3, Radouane Abouqal3, Rachid Bahiri4, Fadoua Allali5, Imane El Bouchti6, Imad Ghozlani7, Hasna Hassikou 8, Taoufiq Harzy9, Linda Ichchou10, Oufae Mkinsi11, Radouane Niamane12, Ahmed bezza1

Rheumatoid Arthritis (RA) is the most prevalent chronic inflammatory rheumatic disease, characterized by functional impairment, which leads to sedentary lifestyle and chronic inflammation. These factors are intertwined with corticosteroid use, which can induce osteoporosis, a significant extra-articular manifestation. Studies have shown controversial results regarding the impact of biologic therapies (bDMARDs) on bone protection, whether through direct or indirect effects on cytokines, ultimately leading to inflammation attenuation and improved quality of life. Consequently, a reduction in degradation factors has been described in groups receiving both bDMARDs and anti-osteoporotic treatments.

Objective: Our primary objective is to determine the prevalence of osteoporosis in RA patients from the Moroccan biologic therapy registry at baseline and after 36 months of biologic therapy in the general population. We also aim to explore various factors associated with osteoporosis based on the type of biologic therapy, including rituximab, anti-TNF, or tocilizumab.

Patients and methods: This is a prospective analytical multicenter study based on data from the Moroccan biologic therapy registry, including 225 patients with RA who meet ACR-EULAR criteria. Osteoporosis status was assessed at baseline (M0) and after 36 months of biologic therapy (M36).

Results: A total of 141 RA patients completed 36 months of treatment with the same biologic medication and were divided into three groups: Group I (n= 98, anti-CD 22), Group II (n= 21, anti-TNFi including infliximab, etanercept, adalimumab, and golimumab), and Group III (n=22, tocilizumab). 15.7% of patients received anti-osteoporotic treatment (AOT) with bisphosphonates, with no significant differences between the three groups (p=0.94). At baseline, 23.6% of patients had osteoporosis, with rates of 25.8%, 19%, and 18.2% in Groups I, II, and III, respectively (p=0.652). Four fracture cases were recorded. FRAX fragility factors were comparable at baseline. Corticosteroid use was observed in 74.7% of patients, with no differences between the groups (p=0.5). Disease Activity Score 28 based on C-reactive protein (DAS28CRP) was higher at M0 compared to M36 (3.40 +/- 2.05) vs. (2.35 +/- 1.47); (p<0.001). Comparing osteoporosis rates between baseline (24.1%) and 3 years (5.7%), a statistically significant decrease in osteoporosis was observed (p<0.001), more pronounced in the AOT group. This decrease was noted within the groups, although the difference was significant only in the rituximab Group I (p<0.001). Multivariate analysis, after adjusting for confounding factors, revealed that osteoporosis was only associated with disease duration (OR=1.002; CI [1.001-1.003]; P<0.004).

Conclusion: Long-term biologic therapy has a beneficial effect on rheumatoid arthritis and, consequently, on bone health. This effect is more pronounced in the group receiving antiosteoporotic treatment. Patients on rituximab showed a significant reduction in osteoporosis.