The Effect of Sodium Bicarbonate (Nephrotrans®) on Calcification Propensity of Serum in Kidney Transplant Recipients

The primary hypothesis (H1) is that the T50 value will change between wash-out and high-dose (3000mg/d) sodium bicarbonate (Nephrotrans®) substitution.

The 0-hypothesis (H0) is that substitution of 3000 mg/d sodium bicarbonate (Nephrotrans®) has no effect on T50-values as compared to wash-out-phase.

Patients will be randomized in a 1:1 ratio to either receive low-dose (1500 mg/d) sodium bicarbonate followed by high-dose (3000mg/d) sodium bicarbonate (sequence A-B) or to receive high-dose sodium bicarbonate followed by low-dose sodium bicarbonate (sequence B-A) with washout-phases in between.

Patients will be randomized in a 1:1 ratio to either receive low-dose (1500 mg/d) sodium bicarbonate followed by high-dose (3000mg/d) sodium bicarbonate (sequence A-B) or to receive high-dose sodium bicarbonate followed by low-dose sodium bicarbonate (sequence B-A) with washout-phases in between. The study will start with an initial run-in wash-out phase, where all sodium bicarbonate or other alkalizing treatment taken by the patient as standard of care will be discontinued. Consequently, there will be a sodium bicarbonate treatment (high dose/low dose) phase, followed by a wash-out phase, followed by another sodium bicarbonate treatment (high dose/low dose) phase, followed by a final wash-out phase. Each study phase, including wash-out phases as well as low-dose and high-dose treatment phases will be 14 ±3 days of duration. Patients will be followed up to 12weeks after randomization until the last study visit of the final wash-out phase.