The Investigators plan to conduct a long-term trial to explore therapeutic implications of effervescent calcium magnesium citrate (EffCaMgCit) in CKD Stage V (end stage renal disease on hemodialysis). The Investigators will test the hypothesis that EffCaMgCit would retard the formation of calciprotein particles (CPP) in CKD Stage V, thereby reducing the degree of coronary artery and peripheral artery calcification and cardiac hypertrophy-fibrosis.

Aim 1. To compare cardiovascular risk of EffCaMgCit versus CaAcS in CKD Stage V Aim 2. To show that EffCaMgCit reduces putative serum FGF23, and increases beneficial alkali load Aim 3. To compare parameters of bone turnover and bone mineral density (BMD) between EffCaMgCit and CaAcS groups

150 adult subjects (> 21 years of age, any cause of CKD) of either gender of any ethnicity with CKD Stage V on hemodialysis will be recruited from Davita-UTSW dialysis centers and randomized into two equal groups in a parallel design, stratified according to gender and age (> or ≤ 50 years). After baseline evaluation, one group (EffCaMgCit Group) will take EffCaMgCit, and the other group (CaAcS Group) will take calcium acetate suspension/solution for two years. Both drugs will be taken 1 sachet each just before or along with breakfast and dinner for the first three months. If tolerated, the dose will be increased to 1 sachet tid just before or along with breakfast, lunch and dinner.

After screening and a baseline evaluation, research personnel will visit patients at the dialysis center every three months for two years. Patients will be evaluated with a medical history, side effect questionnaires, blood pressure measurements, blood tests, echocardiograms, coronary artery calcification analyses, muscle magnesium analyses, and bone mineral density analyses.

It is expected that markers of cardiovascular risk would be improved in patients taking CaMgCit, and would remain stable in those taking CaAcS.

Endpoint Expectations:

• During treatment with EffCaMgCit, T50 would increase (indicative of reduced propensity for CPP formation)
• Serum Mg (inhibitor of CPP formation) would be increased by EffCaMgCit
• An increase in intracellular muscle Mg would show that EffCaMgCit provides a Mg load, and also indicates repletion of Mg stores that might be cardioprotective independently of effects on CPP formation
• The Investigators anticipate that serum FGF23 would be lower and serum Klotho would be higher on EffCaMgCit

Inclusion Criteria:

• Adult subjects (> 21 years of age, any cause of CKD) of either gender of any ethnicity with CKD Stage V on hemodialysis will be recruited. Patients with Type II diabetes and hypertension will be allowed. Treatment with drugs for management of osteoporosis (bisphosphonate, teriparatide, or denosumab) or for chronic kidney disease, customary drugs for hypertension or diabetes, and exogenous estrogen or selective estrogen receptor modulators will be allowed.

Exclusion Criteria:

• Patients with serum Mg > 3.65 mg/dL (3 meq/L) will be excluded (de Francisco, 2010). Also excluded from the study will be those with bowel disease, hypercalcemia, hypophosphatemia (serum P < 2.5 mg/dL) and treatment with adrenocorticosteroids or aluminum-containing antacids or drugs.

To provide adequate blinding, each medication sachet will be labelled with the study name, IRB number, principal investigator's name, expiration date and identification number of the study subject. Labels will be applied to the appropriate medication sachets once the subject has been randomized and assigned to a treatment group. Labelling of the sachets will be done by non-patient care personnel.