Phosphate-binder therapy is associated with reduced mortality in men with non-dialysis-dependent CKD, a study found.

The study, led by Csaba P. Kovesdy, MD, of Salem VA Medical Center in Salem, Va., included 1,188 men (mean age 69 years) with moderate and advanced non-dialysis-dependent CKD at a single medical center. Most patients had CKD stage 3 (57%) or 4 (30%).

Of the 1,188 patients, 344 were treated with a phosphate binder. During a median follow-up of 3.1 years, 658 patients died, for a mortality rate of 141 deaths/1,000 patient-years. Compared with patients who were not treated with phosphate binders, those who were had a 39% decreased risk of death after adjusting for case-mix and laboratory variables. Phosphate binder use was not associated with significant changes in kidney function loss.

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Patients treated with a phosphate binder were more likely to be black, be active smokers, and use calcitriol and aspirin.

“Our results strengthen earlier findings that linked hyperphosphatemia to adverse outcomes in patients with ESRD [end-stage renal disease] and non-dialysis-dependent CKD and should urge us to test phosphorus-lowering therapies in clinical trials,” Dr. Kovesdy and his colleagues concluded.

The researchers said the most plausible explanation for a beneficial impact of phosphate-binder use on mortality is its phosphorus-lowering effect. “The association of phosphate-binder therapy with lower mortality in our study was more pronounced in the subgroup of patients with higher baseline serum phosphorus levels, which suggests that the observed benefit may directly or indirectly be mediated through a hyperphosphatemia-related mechanism of action,” they wrote.

The researchers noted that their study had some potential limitations. The historical and observational nature of the study only allows the establishment of associations and not causal relationships. Patients were not randomly assigned to receive treatment with a phosphate binder so selection bias and unmeasured confounders might be responsible for the observed effects, the authors pointed out. In addition, the study was limited to male patients at a single institution, so the results might not apply to the larger population of non-dialysis-dependent CKD patients.