Calcium Binder Use for Kidney Disease Questioned

A new study challenges the common clinical practice of prescribing high doses of calcium to patients with chronic kidney disease (CKD).

Researchers at the University of Toronto (ON, Canada) and the University of Alberta (Edmonton, Canada) conducted a systematic review of randomized and nonrandomized trials that compared outcomes between patients with CKD taking calcium-based phosphate binders, with those taking non-calcium-based binders. The researchers identified all articles published in any language after Aug 1, 2008, up until Oct 22, 2012, by searching Medline, Embase, International Pharmaceutical Abstracts, Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing and Allied Health Literature.

In all, the researchers identified 847 reports; an analysis of the 11 randomized, controlled trials involving 4,622 patients which met the inclusion criteria showed that patients assigned to non-calcium-based binders, such as sevelamer or lanthanum, had a 22% reduction in all-cause mortality compared with those assigned to calcium-based phosphate binders, as well as reduced calcification of coronary arteries. The study was published early online on July 19, 2013, in the Lancet.

“Doctors commonly prescribe calcium supplements to prevent elevated phosphate levels, which can damage the body, but a growing number of studies have shown calcium supplements may actually increase the risk of heart disease,” said lead author Sophie Jamal, MD, of the University of Toronto. “Our study validates these claims and, for the first time, shows the long-term consequences of taking calcium supplements can be dangerous for patients with kidney disease.”

“What we can say is that the risk of death is lower in those taking non-calcium-based treatments; what we don't know is the exact mechanism of this finding and whether it is that calcium is bad, or that sevelamer and lanthanum are good,” added senior author Ross Tsuyuki, MD, of the University of Alberta. “Some researchers and physicians have been saying for years that kidney disease patients need to get off calcium. Now we think our review shows there is much more solid evidence to argue for that change to clinical practice.”

Phosphate binders (calcium-based and calcium-free) are recommended to lower serum phosphate and prevent hyperphosphatemia in patients with CKD. Calcium binds to the phosphate in the body, eliminating it via the kidneys to the urine. Sevelamer or lanthanum can also get rid of phosphate in the body, but are much more expensive, costing up to 100 times more than calcium.

Related Links:
University of Toronto
University of Alberta