Objectives: The effect of biological disease-modifying anti-rheumatic drugs (bDMARDs) on renal function in patients with rheumatoid arthritis (RA) has not been well established. We assessed whether tumour necrosis factor (TNF) inhibitors could affect renal function in RA.
Methods: A total of 2110 patients with RA enrolled in the Korean College of Rheumatology Biologics (KOBIO) registry were analysed. All patients were taking bDMARDs or conventional synthetic DMARDs (csDMARDs). Renal function was evaluated by calculating the estimated glomerular filter rate (eGFR) using the Modification of Diet in Renal Disease (MDRD) equation. Renal insufficiency was defined as eGFR <60 mL/min/1.73 m2. Differences in eGFR changes between different types of DMARDs were assessed at each follow-up time using the generalised linear model (GLM) method. Risk factors for renal insufficiency were identified using binary logistic regression analysis.
Results: The changes of eGFR values in patients treated with TNF inhibitors were not significantly different from those with csDMARDs alone or non-TNF inhibitors in all RA patients regardless of renal function. Among patients with renal insufficiency, GLM analysis revealed that the changes of eGFR values by TNF inhibitors were also compatible to those treated with csDMARDs alone or non-TNF inhibitors. Older age (>55 years), longer disease duration (>5 years), and use of methotrexate were identified as clinical determinants for renal insufficiency.
Conclusions: TNF inhibitors did not influence the change of renal function during RA treatment. TNF inhibitors may be a safe treatment option irrespective of renal function.