Overall, older age (p < 0.001), glomerulonephritis as a preceding disease (p < 0.001), higher CKD stages (p < 0.001), higher diastolic blood pressure (DBP) (p = 0.029), lower body weight (p = 0.036), proteinuria (p < 0.001), and use of a renin-angiotensin system inhibitor (p = 0.002) were significantly associated with CKD patients with anemia, compared to those without. The gene discussed is REN; the disease is anemia (phenotype).