Primary sclerosing cholangitis causally affects kidney function decline: A Mendelian randomization study

Abstract Background and Aim The causal linkage between primary sclerosing cholangitis (PSC) and kidney function is unexplored despite their potential for long‐term detrimental effects on kidney function. Methods Two‐sample summary‐level Mendelian randomization (MR) study was conducted to identify the association between PSC and kidney function. The genetic variants were extracted from the PSC‐specific multi‐trait analyzed genome‐wide association study (GWAS) of European ancestry. Summary‐level data for kidney function traits, including estimated glomerular filtration rate (eGFR), annual eGFR decline, and chronic kidney disease (CKD), were obtained from the CKDGen consortium. Multiplicative random‐effects inverse‐variance weighted (MR‐IVW), and a series of pleiotropy‐robust analyses were performed to investigate the causal effects and ascertain their robustness. Results Significant causal associations between genetically predicted PSC and kidney function traits were identified. Genetically predicted PSC was associated with decreased log‐transformed eGFR (MR‐IVW; beta = −0.41%; standard error [SE] = 0.02%; P < 0.001), increased rate of annual eGFR decline (MR‐IVW; beta = 2.43%; SE = 0.18%; P < 0.001), and higher risk of CKD (MR‐IVW; odds ratio = 1.07; 95% confidence interval = 1.06–1.08; P < 0.001). The main findings were supported by pleiotropy‐robust analysis, including MR‐Egger with bootstrapped error and weighted median. Conclusions Our study demonstrates that genetically predicted PSC is causally associated with kidney function impairment. Further studies are warranted to identify the underlying mechanisms.