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Dietary Intervention Trial Targeting Metabolic Syndrome After Kidney Transplantation

Not Applicable
Conditions
Kidney Transplant; Complications
Interventions
Other: Dutch Nutritional Guidelines
Other: high-protein, carbohydrate-reduced diet
Registration Number
NCT04698408
Lead Sponsor
University Medical Center Groningen
Brief Summary

Kidney transplant recipients (KTR) have a considerably lower life expectancy as compared with the general population, primarily due to a high prevalence of cardiovascular diseases. KTR often develop an unfavourable cardio-metabolic risk profile characterized by weight gain, metabolic syndrome and post-transplantation diabetes mellitus (PTDM). In general, nutrition plays a key role in both the prevention and treatment of these cardio-metabolic derangements.

However, in KTR most RCT's with a dietary intervention, failed to show significant improvement in cardio-metabolic health. This at least questions the efficacy of the diets of these intervention, which relied on general or diabetes guidelines, after kidney transplantation. KTR not only face a high cardio-metabolic risk, but also have a high risk for malnutrition and muscle mass depletion. More knowledge is required to determine the optimal diet and macronutrient composition for improvement of the cardio-metabolic risk factors in the context of the high malnutrition risk. In this regard, observational studies point towards the needs for a higher protein intake for better patient outcomes. Therefore, in this study, the investigators will examine if a high-protein, carbohydrate-reduced diet is more effective than a diet in line with the Dutch Dietary Guidelines for improvement of cardio-metabolic risk factors and for improvement of the body composition in KTR.

Detailed Description

Not available

Recruitment & Eligibility

Status
UNKNOWN
Sex
All
Target Recruitment
30
Inclusion Criteria
  • Age 18 years or older.
  • Given informed consent.
  • At least 6 months after kidney transplantation.
  • Stable renal function with an estimated glomerular filtration rate (eGFR) > 30 mL/min.
  • Raised systolic blood pressure (≥130 mmHg) and at least two more features of metabolic syndrome: central obesity (waist circumference ≥102 for men and ≥88cm for women), elevated triglycerides (≥ 1.7 mmol/L), reduced HDL-C (< 1.0 mmol/L for men and < 1.3 mmol/L for women) or on drug treatment for reduced HDL, elevated plasma glucose (≥ 5.6 mmol/L) or on drug treatment for elevated glucose9.
  • Approval by nephrologist for participation in the study.
Exclusion Criteria
  • Active medical illness, including rejection of the graft.
  • Psychopathology or serious cognitive impairment.
  • Necessity to follow specific dietary measures for health purposes that conflict with the study diets.
  • Use of insulin or sulfonylurea (SU)-derivates.
  • Language barrier.
  • Pregnancy or lactating.
  • Serum potassium > 5.0 mmol/L that requires dietary measures.
  • Moderate or severe malnutrition (Patient-Generated Subjective Global Assessment (PG-SGA) stage B or C). In this case, patient will be referred to a renal dietician.
  • Participation in other intervention trials.

Study & Design

Study Type
INTERVENTIONAL
Study Design
CROSSOVER
Arm && Interventions
GroupInterventionDescription
Dutch Nutritional GuidelinesDutch Nutritional Guidelines-
high-protein, carbohydrate-reduced diethigh-protein, carbohydrate-reduced diet-
Primary Outcome Measures
NameTimeMethod
Systolic blood pressurebefore and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

Change in systolic blood pressure (in mmHg)

Secondary Outcome Measures
NameTimeMethod
Cardio-metabolic risk factors (lipids)before and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in circulating triglyceride concentrations, low-density lipoprotein cholesterol (LDL-C) and HDL-C (in fasting serum levels) in mmol/L.

Cardio-metabolic risk factors (diastolic blood pressure)before and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

Change in diastolic blood pressure (in mmHg)

Cardio-metabolic risk factors (waist circumference)before and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in waist circumference (WC) in cm

Cardio-metabolic risk factors (insulin resistance)before and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in insulin resistance measuring by the homeostatic model assessment of insulin resistance (HOMA-IR index, fasting glucose, insulin)

Body compositionbefore and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in fat and muscle mass measured by multi-frequency bio-electrical impedance analysis (BIA) BMI, weight

Anthropometric measuresbefore and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

Change in weight in kilograms

Anthropometric measures IIbefore and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

Change in Body Mass Index (BMI) in kilograms per square meter

Body composition IIbefore and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in fat and muscle mass measured by multi-frequency bio-electrical impedance analysis (BIA)

Quality of life (QoL)before and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in QoL, 12-item short form health survey (SF-12)

Fatiguebefore and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in fatigue (measured by Dutch Checklist Individual Strength (CIS-20) questionnaire)

Physical functioningbefore and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in Hand Grip Strength (HSG)

Physical functioning IIbefore and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in the five time sit to stand (FTSTS) test

Nutritional intakebefore and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in nutritional intake measured by a 3-day food diary

Nutritional intake IIbefore and after experimental diet (high-protein, carbohydrate-reduced diet - 6 weeks) / before and after active comparator (Dutch Nutritional Guidelines - 6 weeks) / wash-out period in between (6 weeks)

change in nutritional intake measured by nutritional intake biomarkers from 24-hour urine measurements (sodium, potassium, and urea excretion for calculating the protein intake by use of the Maroni equation)

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