The higher plasma TMAO level was found to be predictive of poor long-term survival in patients without CKD (eGFR ≥ 60 ml/min) irrespective of cystatin C levels implying that increase in TMAO levels may occur before the renal insufficiency (i.e., rise in cystatin C) (Tang et al., 2015b). This evidence concerns the gene CST3 and Renal insufficiency.