Dietary Phosphorus Load and Postprandial Serum Phosphate in HD Patients

Not Applicable

Completed

• Conditions: Hemodialysis
• Interventions: Other: Modified Diet; Other: Standard Diet

• Registration Number: NCT04845724
• Lead Sponsor: University College Cork

Brief Summary

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

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 Timeline

• Study Start: 2016-11-26
• Primary Completion: 2016-12-06
• Study Completion: 2016-12-14
• Status Verified: 2021-04
• Study First Submitted: 2021-04-11
• Study First Submitted QC: 2021-04-11
• Study First Posted: 2021-04-15
• Last Update Submitted: 2021-04-27
• Last Update Posted: 2021-04-30

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 8

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 & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Modified Diet	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.
Standard Diet	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.

Primary Outcome Measures

Name	Time	Method
Serum Phosphate	Post -prandial period (4 hours)	mmol/l

Secondary Outcome Measures

Name	Time	Method
Serum Potassium	Post -prandial period (4 hours)	mmol/l