Dietary Phosphorus Load and Postprandial Serum Phosphate in HD Patients

Study Overview
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Brief Summary
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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
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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).

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

Conditions
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Hemodialysis

Intervention / Treatment
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* Other: Standard Diet
* Other: Modified Diet


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standard Diet<br>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<br> <br> * Other names: Modified Diet;|
| Experimental: Modified Diet<br>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<br> <br> |

What is the study measuring?
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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) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Dietary phosphorus, Hyperphosphatemia, Hyperkalaemia, Phytate, Hemodialysis