Dietary Phosphorus Load and Postprandial Serum Phosphate in HD Patients

The Effect of Dietary Phosphorus Load and Food Matrix on Postprandial Serum Phosphate in Hemodialysis Patients

This study is to investigate the acute postprandial effect of a modified versus standard low phosphorus diet on serum phosphate, potassium and intact parathyroid levels in prevalent hemodialysis (HD) patients

Study Overview

• Status: Completed
• Conditions: Hemodialysis
• Intervention / Treatment: Other: Standard Diet; Other: Modified Diet

Detailed Description

Background: Potential dietary strategies for controlling hyperphosphataemia include the use of protein sources with lower phosphorus bioavailability such as pulses and nuts, focus on phosphorus to protein ratios and the avoidance of all phosphate additives.

Method: Controlled crossover feeding study in 8 HD patients. On one day, participants were directly observed eating a standard low phosphorous diet and on the other day, a modified low phosphorus diet. The modified diet included beef and less dairy, with a lower phosphorus to protein ratio, as well as plant-based protein, whole grains, pulses and nuts containing phytates which reduces phosphorus bioavailability. Both diets were tailored for each participant to provide 1.1g protein/kg ideal body weight. Participants provided fasting bloods before breakfast, a pre-prandial sample before lunch and samples at one hour intervals for the four hours after the meal, for analysis of phosphate, potassium and intact parathyroid hormone (iPTH).

• Study Type: Interventional
• Enrollment (Actual): 8
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• > 18 years of age;
• on dialysis for > 3 months;
• pre-dialysis serum phosphate < 2.5 mmol/L and
• serum potassium < 6.3 mmol/L on most recent routine monthly blood test;
• urinary outputs of < 200 ml/day by self-report;
• being in their usual state of health

Exclusion Criteria:

• history of diabetes mellitus
• history of parathyroidectomy
• history of calciphylaxis

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Standard Diet; The standard diet was based on the current dialysis diet sheet. The standard diet main meal contained a higher proportion of foods with a higher phosphorus to protein ratio (salmon and dairy), and foods with higher phosphorus bioavailability (cake). The diet was tailored for each participant to provide 1.1g protein/kg ideal body weight. The major differences between the diets were at the main meal.	Other: Standard Diet; Other Names: Modified Diet
Experimental: Modified Diet; The modified diet, representative of the proposed modified phosphorus diet used food of lower phosphorus to protein ratio such as beef and less dairy. Approximately 30% dietary phosphorus in the modified diet came from foods with significant phytate content such as pulses, nuts and whole grains. The modified diet was tailored for each participant to provide 1.1g protein/kg ideal body weight.	Other: Modified Diet

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum Phosphate	mmol/l	Post -prandial period (4 hours)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum Potassium	mmol/l	Post -prandial period (4 hours)

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum intact Parathyroid Hormone	ng/L	Post -prandial period (4 hours)

Collaborators and Investigators

• Sponsor: University College Cork
• Investigators: Principal Investigator: Joseph Eustace, MB, University College Cork

Publications and helpful links

General Publications

• Byrne F, Gillman B, Palmer B, Kiely M, Eustace J, Kearney P, Davidson F, Shiely F. The effect of dietary phosphorus load and food matrix on postprandial serum phosphate in hemodialysis patients: a pilot study. HRB Open Res. 2021 Nov 10;4:119. doi: 10.12688/hrbopenres.13382.1. eCollection 2021.

Study record dates

Study Major Dates

• Study Start (Actual): November 26, 2016
• Primary Completion (Actual): December 6, 2016
• Study Completion (Actual): December 14, 2016

Study Registration Dates

• First Submitted: April 11, 2021
• First Submitted That Met QC Criteria: April 11, 2021
• First Posted (Actual): April 15, 2021

Study Record Updates

• Last Update Posted (Actual): April 30, 2021
• Last Update Submitted That Met QC Criteria: April 27, 2021
• Last Verified: April 1, 2021

More Information

Terms related to this study

• Keywords: Hemodialysis; Hyperphosphatemia; Hyperkalaemia; Dietary phosphorus; Phytate
• Other Study ID Numbers: 16-CRFC-32

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: We did not get consent for publication of identifiable data, and so as perHrynaszkiewicz et al 2010 anthropometric data, sex, ethnicity and age will not be reported in the raw data. We will report the biochemical data and nutrient intake data which allow the reproduction of the analysis we will present.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No