Progression of cardiac valve calcification and decline of renal function in CKD patients.

Background: No study has evaluated the efficacy of non-calcium-containing phosphate binders in slowing progression of cardiac valve calcification or deterioration of kidney function in patients with chronic kidney disease not on dialysis. This study addressed these issues.

Methods: Outpatients (n = 170) with stage 3-4 chronic kidney disease and either mitral or aortic valve calcification were evaluated in this single-center, single-arm, prospective observational study. Patients received sevelamer hydrochloride (1,600 mg/day) for 1 year. Cardiac valve calcification progression was assessed by echocardiography, and decline of renal function by estimated glomerular filtration rate. Parathyroid hormone, FGF-23 and C-reactive protein (CRP) serum concentration and urinary phosphorus excretion were assayed.

Results: At the end of treatment with sevelamer (12th month), mitral valve calcification had decreased by 79.3% from baseline. At baseline, 69 patients had grade 1, 97 patients grade 2 and 4 patients grade 3 calcification scores; at the end of the study, 60 patients showed grade 1, and no mitral valve calcification was registered in the remaining patients. An aortic valve score of 1 was found in 32%, score of 2 in 58%, score of 3 in 9% and score of 4 in 1% of patients at baseline; at the end of the study, a score of 1 was found in 95% and a score of 2 in 5% of patients. Significant slowing down of renal function decline (p<0.001), reduction of FGF-23 and CRP concentration (p<0.0001) and phosphorus excretion (p<0.0001) were observed.

Conclusions: One-year treatment with a non-calcium-containing phosphate binder may hamper the progression of cardiac valve calcification and slow the decline of renal function, as well as reduce serum concentration of FGF-23 and CRP and urinary phosphorus excretion.