Longitudinal changes in renal function in patients with rheumatoid arthritis: a retrospective observational study in Japan

Abstract

Aim: This retrospective observational study of adults in Japan investigated the impact of rheumatoid arthritis（RA）diagnosis, risk factors of interest and antirheumatic drugs on changes in renal function.

Methods: Medical records were extracted from the Real-World Data database between 1 July 2011 and 3 March 2023. Patients were categorized into RA/non-RA groups and matched using exact and propensity score matching. The primary endpoint was difference in slope of estimated glomerular filtration rate（eGFR）over time between RA and non-RA patients, both overall and by subgroups of interest. Other endpoints included differences in eGFR slope between RA patients with/without the use of pre-defined medications, and in RA patients diagnosed prior to index date and previously treated with methotrexate（MTX）.

Results: After matching, 29,062 patients were included（n=14,531 for RA/non-RA groups）. Minimal difference in eGFR slope was observed between RA/non-RA patients（−0.05mL/min/1.73m²/year）; no trends emerged following subgroup analyses. MTX and tacrolimus use was negatively associated with changes in eGFR in RA patients. Patients diagnosed with RA before enrolment and who received MTX monotherapy had a steeper negative eGFR slope versus both overall groups（RA/non-RA）.

Conclusion: Our findings highlight the need for monitoring renal function in RA patients prescribed antirheumatic drugs.