Clinical trial NCT03146923: Decreasing Intakes & Absorption of Phosphorus in Haemodialysis Patients Through Food Choices
Official title: Decreasing Intakes & Absorption of Phosphorus in Haemodialysis Patients Through Food Choices
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Renal Dialysis
Hyperphosphatemia
Dietary Modification
Lead sponsor: University College Cork
Sponsor class: OTHER
Collaborators: name: Cork University Hospital
name: Irish Nutrition & Dietetic Institute
First posted: 2017-05-10
Enrollment: 74
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Multicentre Parallel Arm Randomised Controlled Trial
Primary purpose: TREATMENT

Brief summary: Based on new evidence renal dietitians in Ireland are revising the diet sheet that is used to teach patients about reducing blood phosphate. Changes that renal dietitians plan to make to the dietary phosphorus prescription

* Inclusion of some nuts and pulses
* More detailed education re phosphate additives
* More accurate protein prescription
* Inclusion of more whole grains
* Encouraging the use of foods with a low phosphorus to protein ratio

The investigators want to test the two diet prescription to find out, which one is better at reducing blood phosphate and which one is more acceptable to patients. The investigators also want to make sure it is safe.

Detailed description: Background:

Chronic Kidney Disease (CKD) afflicts one in twenty Irish citizens who are over age 45 and is a significant risk factor for cardiovascular disease, premature death and significantly impacts healthcare utilisation. As kidney function deteriorates, phosphorus, upregulates counter regulatory hormones (immunoreactive Parathyroid Hormone (iPTH) and Fibroblast Growth Factor 23 (FGF23), the elevated levels of which are maladaptive. Collectively these abnormalities and their complications are referred to as Chronic Kidney Disease, Mineral \& Bone Disorder (CKD MBD). Hyperphosphataemia or high blood phosphate levels is associated with increased mortality, in dialysis patients, in the earlier stages of CKD and even in patients with normal renal function. The use of phosphorus restricted diets in combination with oral phosphate binders has become well established in the management of patients with CKD stages 3-5 (including CKD stage 5D).

Experts have called for research into the dietary management of phosphate in the CKD population. The current evidence base is weak and in a recent Cochrane systematic review the authors concluded that there was limited low quality evidence to indicate that dietary interventions may positively affect CKD-MBD.

In recent years there has been increased focus on dietary phosphorus restriction in the management of CKD-MBD and a number of experts have suggested changes in how we manage dietary phosphorus. Several potential strategies have been suggested and in response the Renal Interest Group (RIG) of the Irish Nutrition \& Dietetic Institute (INDI) held a 1 day meeting in Dublin in January 2015 which brought together numerous experts in the field to summarise our current understanding and the recent advances in the field.

Following on from this, RIG set up a working group to translate the new knowledge from the advanced study day and from further literature reviews into a modified low phosphate diet sheet.

Almost all people who have end stage kidney disease (ESKD) and require dialysis to survive, follow a dietary phosphorus restriction, to control high blood phosphate, with the aim of reducing the risk of cardiovascular disease, fractures and death.

Research Hypothesis: The modified low phosphate diet sheet is superior to current treatment in haemodialysis patients

Study Objectives

Primary Objective: To determine if the modified low phosphorus dietary prescription is superior to current management in reducing serum phosphate levels in HD patients

Secondary Objectives To determine if the modified low phosphorus diet is tolerable To determine if the modified low phosphorus diet is safe To determine if the modified low phosphorus diet brings the renal diet closer to healthy eating advice e.g. increased fibre intake.

Eligibility criteria: Inclusion Criteria:

* \>18 years
* Self reported urine output less than 2 cups (400mls) / day
* On maintenance haemodialysis for \> 3 months
* Phosphate \>1.6mmole/L on average of last 3 available routine monthly blood tests

Exclusion Criteria:

* Hyperkalemia, defined as a predialysis serum K on routine monthly blood test of \>6mmoles/l in the month preceding the trial.
* Parathyroidectomy
* Corrected serum calcium \<2.2 or \> 2.6mmol/L or local normal units where ranges varied significantly from 2.2-2.6mmoles/l.
* Acute concurrent illness, requiring hospitalisation in the 2 weeks prior to recruitment.

Primary outcomes:
measure: Serum Phosphate
timeFrame: 1 month
Secondary outcomes:
measure: Dietary Intake
timeFrame: 1 month
measure: Serum iPTH
timeFrame: 1 month
measure: Palatability and Subject Acceptance (Tolerability)
timeFrame: 1 month
measure: FGF23 (Exploratory Endpoint)
timeFrame: 1 month
measure: Serum Potassium (Safety Endpoints):
timeFrame: 1 month
Other outcomes:
Locations:
city: Tullamore
country: Ireland
facility: Midland Regional Hospital Tullamore
state: Offaly
city: Cavan
country: Ireland
facility: Cavan General Hospital
city: Cork
country: Ireland
facility: Fiona Byrne
city: Dublin
country: Ireland
facility: St. Vincents University Hospital
city: Dublin
country: Ireland
facility: Mater Misericordia University Hospital
city: Dublin
country: Ireland
facility: Beaumont Hospital
city: Dublin
country: Ireland
facility: Tallaght Hospital
city: Galway
country: Ireland
facility: Galway University Hospitals
city: Limerick
country: Ireland
facility: University Hospital Limerick
city: Mayo
country: Ireland
facility: Mayo University Hospital
Study officials:
affiliation: HRB Clinical Research Facility
name: Joseph Eustace, MB
role: PRINCIPAL_INVESTIGATOR
References:
citation: Byrne F, Gillman B, Renal Interest Group INDI, Eustace J. Multicentre Randomized Control Trial of Phosphate Control with a Modified as Compared to Standard Renal Diet TH-OR030. J Am Soc Nephrol 2018;29:8.