Postdialysis serum phosphate equilibrium in hemodialysis patients on a controlled diet and no binders

Elizabeth Stremke, Laurie Trevino, Simit Doshi, Ranjani N. Moorthi, Kathleen M. Hill Gallant, Sharon M. Moe

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Background: Studies evaluating the change in serum phosphate post hemodialysis (HD) demonstrate an initial decline during dialysis but a rebound post dialysis. However, previous studies were done on usual diet and phosphate binders, with limited number of blood draws, confounding conclusions. We determined serum phosphate reduction, rebound, and equilibrium over 48 h in HD patients consuming a controlled, low phosphorus diet without binders. Methods: Serum phosphate (mg/dL) was analyzed before and after a HD treatment and frequently during the ensuing 48 h intradialytic period in the clinical research unit. Thirteen subjects were enrolled and had been off phosphate binders for 10 days and consumed a standardized low phosphate (900 mg/day) diet for 3 weeks prior to the assessments. Linear regression was used to determine relationships between the pre-HD serum phosphate, decline post-HD (post-HD drop); and a 48 h area under curve (AUC) using the trapezoidal method as a measure of overall phosphate levels from the end of dialysis to 48 h post dialysis. Repeated Measures ANOVA with Dunnett's posthoc test was used to determine rebound. Results: Five of 13 subjects returned to >90% of their pre-HD serum phosphate within the first 24 h post-HD, and serum phosphate was 94 ± 0.11% (range 63%–113%) by 48 h after the completion of HD. The 48 h AUC of serum phosphate during the interdialytic period was correlated with both pre dialysis phosphorus (r = 0.85; p = 0.0002) and the pre-post drop in serum phosphate during dialysis (r = 0.69; p = 0.0085). In contrast, the net ultrafiltration was not related to the 48 h AUC of serum phosphorus (r = 0.20; p = 0.51). Conclusions: In hemodialysis patients on standard low phosphorus diet and no phosphate binders, the interdialytic serum phosphorus level, assessed as AUC, is determined by the pre dialysis phosphorus and net-change in serum phosphorus during the dialysis treatment, but not the ultrafiltration volume [Correction added on 25 January, after first online publication: In the last sentence of the Abstract, the word “potassium” has been replaced with “phosphorus” to improve accuracy.].

Original languageEnglish (US)
Pages (from-to)255-263
Number of pages9
JournalHemodialysis International
Issue number2
StatePublished - Apr 2022

Bibliographical note

Funding Information:
SMM receives consulting fees from Amgen and Ardelyx, and grant support from Chugai (for this study) and Keryx/Akebia. All grants were paid directly to Indiana University.

Funding Information:
The parent study was funded by Chugai Pharmaceutical, Co., Tokyo, Japan but these sponsors did not have a role in this study design, analyses or interpretation. The study was conducted in the Indiana Clinical Research Center, funded in part by UL1TR00259 from the NIH National Center for Advancing Translational Sciences. The project was supported in part by National Institute of Diabetes and Digestive and Kidney Disorders (NIH) Awards K01 DK102864 (KMHG), K23 DK102824 (RNM); the Indiana Clinical and Translational Science Institute funded in part by NIH Award Number UL1 TR002529; ERS received support in part through NIH Award Numbers TL1 TR002531 and T32 HL007779. SMM was funded by NIH RO1DK110871, P30AR072581, UL1TR002529, and VA Merit I01 BX001471.

Publisher Copyright:
© 2021 International Society for Hemodialysis.


  • diet
  • hemodialysis
  • phosphorus


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