Multidisciplinary Team versus a "Phosphate-Counting" App for Serum Phosphate Control: A Randomized Controlled Trial

Abstract

Background: Hyperphosphatemia is almost universal in well-nourished patients with ESKD treated with dialysis due to an imbalance between dietary intake and phosphate removal via residual kidney function and dialysis. Although food phosphate content can vary dramatically between meals, the current standard is to prescribe a fixed dose of phosphate binder that may not match meal phosphate intake. The primary objective of our study was to determine if the use of an app that matches phosphate binder dose with food phosphate content would be associated with an improvement in serum phosphate and a reduction in calcium carbonate intake compared with the multidisciplinary renal team.

Methods: Eighty patients with ESKD treated with peritoneal dialysis at a tertiary care hospital in Canada were randomized to the standard of care for serum phosphate management (multidisciplinary renal team) versus the OkKidney app. Serum phosphate was measured at baseline and then monthly for 3 months with adjustments to phosphate management as deemed necessary by the multidisciplinary team (control) or the phosphate binder multiplier in the OkKidney app (intervention) on the basis of the laboratory values. The primary analysis was an unpaired t test of the serum phosphate at study completion.

Results: The participants were 56 (±14) years old, and 54% were men; the most common cause of ESKD was diabetes mellitus. The serum phosphate values were 1.96 (0.41) and 1.85 (0.44) mmol/L in the control and intervention groups, respectively, at the end of 3 months (P=0.30). The median elemental daily dose of calcium carbonate did not differ between the groups at study completion (587 mg [309-928] versus 799 mg [567-1183], P=0.29).

Conclusions: The OkKidney app was associated with similar but not superior serum phosphate control to the standard of care, which included renal dietician support.

Clinical trial registry name and registration number: US National Library Medicine ClinicalTrials.gov, NCT01643486.

Keywords: hyperphosphatemia; mineral metabolism; peritoneal dialysis; phosphate; phosphate binders; randomized controlled trial.

Conflict of interest statement

B. McCormick, K. Wilson, and D. Zimmerman report receiving salary support from the Department of Medicine at the Ottawa Hospital. D. Zimmerman reports receiving research funding from GSK; honoraria from Otsuka; being a scientific advisor or member with Otsuka; and other interests/relationships with Alive to Strive (not for profit) and the Canadian Society of Nephrology (past president). All remaining authors have nothing to disclose.

Copyright © 2021 by the American Society of Nephrology.

Figures

Graphical abstract

Figure 1.

Phosphate-counting application.

Figure 2.

Study flow diagram. ICU, intensive care unit.

Figure 3.

Scatterplot of the effect of baseline serum phosphate.