Lower serum calcium is independently associated with CKD progression

Area of Science:

• Nephrology
• Endocrinology
• Metabolic Bone Disease

Background:

• Calcium metabolism disturbances are frequent in chronic kidney disease (CKD).
• The relationship between serum calcium levels and the progression of kidney function decline in CKD patients remains unclear.
• Understanding this association is crucial for managing CKD progression.

Purpose of the Study:

• To investigate the association between baseline serum calcium levels and the rate of estimated glomerular filtration rate (eGFR) decline in adults with CKD stages 3-5.
• To explore potential modifying effects of vitamin D supplementation on this association.

Main Methods:

• A cohort study of 15,755 adult Stockholm citizens with CKD stages 3-5 was analyzed.
• Baseline serum calcium and creatinine levels were measured between 2006-2011.
• Linear mixed models were used to assess the association between baseline serum calcium and annual eGFR decline (CKD-EPI formula).

Main Results:

• Higher baseline serum calcium was associated with slower eGFR decline in advanced CKD stages (3b-5).
• Each mg/dL increase in serum calcium was linked to a significant protective effect on eGFR decline in CKD stages 3b, 4, and 5.
• The association between serum calcium and CKD progression was attenuated in patients using vitamin D supplements, particularly in stages 3b and 4.

Conclusions:

• In individuals with CKD stages 3b-5, lower baseline serum calcium is associated with more rapid kidney function decline.
• Low serum corrected calcium may serve as an indicator of vitamin D deficiency in CKD patients.
• Maintaining adequate calcium levels, potentially through vitamin D supplementation, may be important for slowing CKD progression.