Efficacy and safety of first-line biological DMARDs in rheumatoid arthritis patients with chronic kidney disease.

Objective: To evaluate the efficacy and safety of first-line biological disease-modifying antirheumatic drugs (bDMARDs) in patients with rheumatoid arthritis (RA) with chronic kidney disease (CKD), including those undergoing haemodialysis (HD).

Methods: This retrospective cohort study included 425 patients with RA prescribed their first bDMARDs at two hospitals from 2004 to 2021. Patients were categorised by kidney function and bDMARD modality (TNFα inhibitors (TNFαis), interleukin-6 inhibitors (IL-6is), cytotoxic T-lymphocyte antigen-4 immunoglobulin (CTLA4-Ig)). The primary outcome was the 36-month drug retention rate, with secondary outcomes including changes in Disease Activity Score 28 (DAS28)-C reactive protein (CRP)/erythrocyte sedimentation rate (ESR), prednisolone dosage and reasons for discontinuation.

Results: The 36-month drug retention rates by estimated glomerular filtration rate (eGFR) (≥60, 30-60, <30 mL/min/1.73 m²) were as follows: all bDMARDs (45.2%, 32.0%, 41.4%), TNFαis (45.3%, 28.2%, 34.0%), IL-6is (47.4%, 66.7%, 71.4%) and CTLA-4Ig (50.0%, 31.3%, 33.3%). Even in groups with lower kidney function, the drug retention rate of bDMARDs was generally maintained. However, the retention rate of TNFαis was significantly lower in patients with eGFR <30 mL/min/1.73 m². IL-6is showed the highest retention rate and the lowest discontinuation rate due to ineffectiveness in this group (HR 0.11, 95% CI 0.02 to 0.85, p=0.03). All bDMARDs improved DAS28-CRP/ESR and reduced prednisolone dosage across all groups.

Conclusion: bDMARDs demonstrated effective and safe profiles in patients with RA with CKD, even among patients on HD. In particular, IL-6is had a significantly higher drug retention rate in patients with an eGFR of <30 mL/min/1.73 m² and fewer discontinuations due to ineffectiveness. IL-6is were more efficacious as monotherapy compared with the other bDMARDs.