Background

Phosphorus binders are used to treat hyperphosphatemia in maintenance dialysis patients, in whom the use of these medications has been associated with lower mortality in some observational studies. It is not clear whether similar benefits can be seen in patients with non-dialysis-dependent chronic kidney disease (CKD).

Study design

Historical cohort.

Setting & participants

1,188 men with moderate and advanced non-dialysis-dependent CKD at a single medical center.

Predictor

Administration of any phosphorus binder.

Outcomes & measurements

We examined associations of any phosphorus-binder administration with all-cause mortality and the slopes of estimated glomerular filtration rate using time-varying Cox models and mixed-effects models. Associations also were examined in intention-to-treat analyses and in 133 patient-pairs matched according to propensity scores.

Results

344 patients were treated with a phosphorus binder; 658 patients died (mortality rate, 141 deaths/1,000 patient-years; 95% CI, 131-153) during a median follow-up of 3.1 years. Treatment with phosphorus binders was associated with significantly lower mortality (adjusted HR, 0.61; 95% CI, 0.45-0.81; P < 0.001). Results were similar when exposure was modeled in intention-to-treat analyses and examining propensity-matched patients. Phosphorus-binder use was not associated with significant changes in kidney function loss.

Limitations

Results may not apply to all patients with non-dialysis-dependent CKD.

Conclusions

Administration of phosphorus binders is associated with lower mortality in men with moderate and advanced non-dialysis-dependent CKD. Clinical trials are needed to determine the risks and benefits of phosphorus-binder use in this patient population.

Background and objectives

Elevated serum calcium has been associated with increased mortality in dialysis patients, but it is unclear whether the same is true in non-dialysis-dependent (NDD) chronic kidney disease (CKD). Outcomes associated with low serum calcium are also not well-characterized.

Design, setting, participants, & measurements

We examined associations of baseline, time-varying, and time-averaged serum calcium with all-cause mortality in a historic prospective cohort of 1243 men with moderate and advanced NDD CKD by using Cox models.

Results

The association of serum calcium with mortality varied according to the applied statistical models. Higher baseline calcium and time-averaged calcium were associated with higher mortality (multivariable adjusted hazard ratio (95% confidence interval): 1.31 (1.13, 1.53); P < 0.001 for a baseline calcium 1 mg/dl higher). However, in time-varying analyses, lower calcium levels were associated with increased mortality.

Conclusions

Higher serum calcium is associated with increased long-term mortality (as reflected by the baseline and time-averaged models), and lower serum calcium is associated with increased short-term mortality (as reflected by the time-varying models) in patients with NDD CKD. Clinical trials are warranted to determine whether maintaining normal serum calcium can improve outcomes in these patients.