In a recent study, researchers were unable to find a
correlation between serum levels of calcium and parathyroid hormone and the
risk for CV mortality or all-cause death in patients with chronic kidney
disease, although higher serum phosphorus in this population was linked with
increased mortality risk.
This systematic review and meta-analysis included 47
cohort studies with a total of 327,644 patients. All studies measured the
association between death and CV events and serum levels of phosphorus,
parathyroid hormone or calcium, which are recommended in clinical practice
guidelines for the management of mineral and bone disorders related to chronic
kidney disease (CKD).
According to data, the risk for all-cause mortality
increased with each 1-mg/dL increase in serum phosphorus (RR=1.18), but the
likelihood of death remained largely unchanged with increased serum levels of
parathyroid hormone (per 100-pg/mL increase, RR=1.01) and calcium (per 1-mg/dL
increase, RR=1.08). Similarly, rates of
mortality were only slightly affected with increased levels of serum
phosphorus (RR=1.10), parathyroid hormone (RR=1.05) or calcium (RR=1.15).
These data, the researchers wrote, do not support the
hypothesis that individuals with CKD should have treatment to achieve targeted
levels of serum parathyroid hormone or calcium to reduce mortality or CV
morbidity, “except at extreme levels in which hypocalcemia and
hypercalcemia result in immediate, clinically apparent adverse events such as
tetany and seizures,” they said. “Furthermore, treating high
phosphorus levels is linked to a substantial pill burden that is associated
with lower quality of life in individuals with
CKD. While we do not conclude that normalizing serum levels
of calcium or phosphorus or avoiding upper or lower extremes of serum level of
parathyroid hormone is futile, high-quality evidence is required before
specific treatment should be advocated strongly.”
However, extrapolating this research into clinical
guidelines currently, wrote Bryan Kestenbaum, MD, with the University of
Washington, Seattle, in an accompanying editorial, remains premature.
“Placebo-controlled clinical trials are the
necessary next step to determine the risks and benefits of treatments that
target mineral metabolism disturbances in patients with CKD as a means to
improve their health,” he said.
Disclosure: Dr. Kestenbaum reported no relevant conflicts of