To compare the effect of lanthanum carbonate with calcium carbonate on serum FGF23 levels in hemodialysis patients.

The investigators enrolled patients on maintenance hemodialysis and randomized them to two groups. One group will receive lanthanum carbonate and another group will receive calcium carbonate. The investigators will compare serum FGF23 levels between two groups after they receive above medication for 6 months.

Inclusion Criteria:

• Age > 18 years old
• Chronic renal failure on maintenance hemodialysis 3 times a week for at least 3 months Serum calcium:8-10.5 mg/dL
• Serum phosphate:3.5-6 mg/dL(before washout period)
• Serum phosphate ≧6 mg/dL after washout period
• Serum i-PTH: 150-600 pg/mL

Exclusion Criteria:

• Diabetes mellitus
• Post parathyroidectomy
• Life expectancy< 6 months
• Liver disease(hepatitis B,C or liver dysfunction)
• Severe gastrointestinal disorders or other severe comorbidity
• Poor compliance
• Intolerance to lanthanum or calcium carbonate
• Active infection
• Malnutrition(serum albumin<3 g/dL or clinical assessment)
• Kt/V< 1.2 (inadequate dialysis)
• Serum phosphate>7.5 mg/dL after washout period