CST3 and renal fibrosis: The results showed that U-EXO hsa_circ_0036649 effectively distinguished renal fibrosis, with the largest AUC of 0.706 (95% CI, 0.606–0.807; p = .001) higher than that of Scr (AUC of 0.575; 95% CI, 0.453−0.697; p = .214), BUN (AUC of 0.479; 95% CI, 0.358–0.601; p = .732), cystatin c (AUC of 0.572; 95% CI, 0.454–0.689; p = .235), eGFR (AUC of 0.573; 95% CI, 0.452–0.695; p = .224) and 24 h proteinuria (AUC of 0.579; 95% CI, 0.459–0.700; p = .189).