Low serum calcium is associated with poor renal outcomes in chronic kidney disease stages 3-4 patients (BMC Nephrology)

Background: Mineral disorders are associated with adverse renal outcomes in chronic kidney disease (CKD) patients. Previous studies have associated hypercalcemia and hypocalcemia with mortality; however, the association between serum calcium and renal outcome is not well-described. Whether adding calcium besides phosphorus or in the form of calcium-phosphorus (Ca x P) product into the model of survival analysis could improve the prediction of renal outcomes is not known. Methods: A prospective cohort of 2144 outpatients with CKD stages 3-4 was evaluated. Cox proportional hazard analysis was performed according to calcium quartiles. Results: The mean calcium level was 9.2 +/- 0.7 mg/dL. Low serum calcium (