Practice patterns of phosphate binder use and their associations with mortality in chronic kidney disease

Background: Higher serum phosphorus is associated with an increased mortality among those with chronic kidney disease (CKD). We examined the practice patterns of phosphate binder use to lower serum phosphorus levels and their associations with mortality in the non-dialysis-dependent CKD population. Methods: We examined the factors associated with the use of calcium and non-calcium phosphate binders in those with stage 3 and 4 CKD (eGFR 15 - 59 mL/min/1.73 m²) using logistic regression models. The associations between phosphate binder use and mortality were studied using propensity based analysis. Results: Out of 57,928 patients with eGFR 15 - 59 mL/min/1.73 m², 13,325 (23%) patients had serum phosphorus levels measured. 945 patients were prescribed phosphate binders, with 238 (25%) of them prescribed non-calcium-based phosphate binders and the rest calcium-based phosphate binders. Higher BMI, higher serum phosphorus, and higher serum calcium were associated with higher odds of being prescribed a non-calcium-based binder. Phosphate binder use was not significantly associated with mortality in either the entire cohort or the matched cohort in the analysis limited to those who were treated for at least 6 months. In the matched cohort, those who were treated for 1 year with a phosphate binder had a non-significant lower mortality rate (hazard ratio (HR): 0.85, 95% CI 0.66, 1.10). Conclusions: Phosphate binder use for 6 months and 1 year was not associated with reduced mortality in those with stage 3 and stage 4 CKD.