Association between Rheumatoid Arthritis and Renal Function: A Bidirectional Mendelian Randomization Study

Abstract This article investigates whether there is a causal relationship between Rheumatoid arthritis (RA) and renal function (measured by estimated glomerular filtration rate) using Mendelian randomization method. The appropriate single nucleotide polymorphisms were extracted from the GWAS of RA and eGFR as gene instrumental variables. Bidirectional two-sample MR analyses were conducted using inverse variance weighting, weighted median method, and MR Egger regression. The outcome and exposure populations were both East Asians. After screening, a total of 11 single-nucleotide polymorphisms (SNPs) of genome-wide significance were included as RA instrumental variables. The analysis did not show a significant correlation between RA and eGFR (β = 0.007, P = 0.717 in IVW method). Likewise, using 54 genome-wide significant SNPs as eGFR instrumental variables, no causal relationship between eGFR and RA was found (odds ratio = 0.890, 95% CI: 0.691—1.144, p = 0.363). Methods such as MR-Egger regression and weighted median also support the result that there is no evidence of any causal relationship between RA and eGFR in any direction, except for the IVW method.