Comparing the 3 groups, there were significant differences in 12 variables including age (0 < 50y, 1 ≧ 50y), gender (0 = male, 1 = female), smoking (0 = none, 1 = yes), hypertension (0 = none, 1 = yes), diabetes (0 = none, 1 = yes), CKD etiology (1 = chronic glomerulonephritis, 2 = diabetic nephropathy, 3 = hypertensive nephropathy, 4 = other), anemia (0 = none, 1 = yes), FGF23 (1< 800 ng/L=, 2 ≧ 800 ng/L), calcium (0 < 2.3 mmol/l, 1 ≧ 2.3 mmol/l), phosphorus (0 < 2 mmol/l, 1 ≧ 2 mmol/l), potassium (0 < 5.2 mmol/l, 1 ≧ 5.2 mmol/l), duration of CKD (1 < 30 months, 2 ≥ 30 months). This evidence concerns the gene FGF23 and anemia.