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Dietary Polyphenols and Glycation in Renal Insufficiency (PoGlyDRI)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT02524938
Recruitment Status : Recruiting
First Posted : August 17, 2015
Last Update Posted : February 28, 2019
University of Glasgow
Information provided by (Responsible Party):
NHS Greater Glasgow and Clyde

Brief Summary:

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of kidney failure, with high levels of glycohaemoglobin (HbA1c) presenting a sharper decline in renal function and an increase in the risk of mortality and end-stage renal disease (ESRD). Polyphenols may improve renal insufficiency in patients with diabetes with chlorogenic acids (CGA) one of the principle polyphenol groups in the diet - coffee/tea, stone fruits (especially plums/prunes) and some vegetables (artichoke, chicory). CGA (3-4 cups of coffee) has been associated with 25% lower risk of T2DM and a favourable reduction of HbA1c, blood pressure, and oxidative stress levels. This randomised controlled trial, therefore, aims to evaluate the effect of high CGA food on glycation and oxidative stress in T2DM subjects with early renal insufficiency (glomerular filtration rate of 35-60 mL/min) as well as progression of renal insufficiency and the risk of cardiovascular diseases.

The study will have two phases - phase I, an interventional study of 3 months followed by phase II, an observational study of 21 months.

In phase I, subjects will be randomized into 2 groups: CGA-enriched diet group, or control (habitual) diet group. The treatment group will be provided with a chlorogenic acid-rich food (coffee) with instructions to achieve an intake of 400 mg per day (equivalent to 3-4 coffee cups per day) for 12 weeks. The control group will receive a conventional coffee low in chlorogenic acid.

Participants will attend three sessions during phase I; baseline, 6 weeks, and 12 weeks. At baseline, general information, medical history, dietary habits and medication use will be recorded and a Food Frequency Questionnaire completed. Urine and blood samples will be collected and blood pressure, waist circumference, height and weight recorded. Participants' diet over the previous 3 days will be assessed by estimated food diary analysis.

In phase II, written dietary recommendations will be provided at three time points (months 6, 12 and 24) - treatment group to achieve a CGA-rich diet (total polyphenol intake of at least 1g per day, and at least 400mg per day of CGA) and standard dietary advice for the control group. Anthropometric/dietary data will be collected as well as blood and urine samples to assess markers of renal function, glycation and oxidative stress, and proteomic markers of cardiovascular disease, coronary artery disease and diabetes.

Condition or disease Intervention/treatment Phase
Diabetes Mellitus, Type 2 Renal Insufficiency, Chronic Dietary Supplement: Chlorogenic Acid (CGA) enriched coffee Dietary Supplement: Conventional coffee Not Applicable

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 118 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: PoGlyDRI - Impact of Dietary Polyphenols on Protein Glycation in Type 2 Diabetes Mellitus Subjects With Chronic Renal Insufficiency
Actual Study Start Date : June 1, 2016
Estimated Primary Completion Date : November 2020
Estimated Study Completion Date : November 2020

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Treatment group
Chlorogenic Acid (CGA) 400mg/day (CGA-enriched coffee)
Dietary Supplement: Chlorogenic Acid (CGA) enriched coffee

Chlorogenic Acid (CGA) enriched coffee Phase I: CGA-enriched coffee provided with a CGA content of 70-90 mg/100g. Daily CGA intake of 400mg.

Phase II: recommendation for achieving a CGA-rich diet of at least 400mg/day (total polyphenol intake of at least 1g/day)

Other Name: CGA-enriched diet

Sham Comparator: Control group
Conventional coffee (habitual diet)
Dietary Supplement: Conventional coffee
Phase I: conventional coffee provided (low in CGA) Phase II: standard dietary advice
Other Name: Habitual diet

Primary Outcome Measures :
  1. Change in glycohaemoglobin (HbA1c) [ Time Frame: 3 months ]
  2. Change in estimated glomerular filtration rate (eGFR) [ Time Frame: 21 months ]

Secondary Outcome Measures :
  1. Change in fasting glucose [ Time Frame: 3 months ]
  2. Change in fructosamine [ Time Frame: 3 months ]
  3. Change in advanced glycation end product (AGE) [ Time Frame: 3 months ]
  4. Change in soluble receptor for AGE (sRAGE) [ Time Frame: 3 months ]
  5. Change in F2-isoprostane [ Time Frame: 3 months ]
  6. Change in malondialdehyde (MDA) [ Time Frame: 3 months ]
  7. Change in Urinary Albumin Excretion [ Time Frame: 21 months ]
  8. Change in creatinine [ Time Frame: 21 months ]
  9. Change in blood pressure [ Time Frame: 21 months ]
  10. Change in crystatin C [ Time Frame: 21 months ]
  11. Change in fibrinogen [ Time Frame: 21 months ]
  12. Change in cholesterol [ Time Frame: 21 months ]
  13. Change in C-reactive protein [ Time Frame: 21 months ]
  14. Change in Interleukin-6 [ Time Frame: 21 months ]
  15. Change in thiobarbituric acid reactive substances (TBARS) [ Time Frame: 21 months ]
  16. Change in advanced oxidation protein products (AOPP) [ Time Frame: 21 months ]
  17. Change in 8hydroxy 2'deoxyguanoside (8OhdG) [ Time Frame: 21 months ]

Information from the National Library of Medicine

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Ages Eligible for Study:   40 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • type 2 Diabetes Mellitus
  • chronic renal insufficiency with persistent eGFR of 35-60mL/min for at least three months
  • fluent in English

Exclusion Criteria:

  • dialysis therapy (current or previous)
  • malignancy
  • transplant recipient
  • hyperthyroidism
  • hypothyroidism
  • high dose glucocorticoids (≥250 mg)
  • body mass index (BMI) ≥ 45 kg/m2
  • special dietary requirements
  • take creatine, antioxidants or vitamin supplements
  • smoker
  • pregnant
  • consume >4 cups of tea/coffee per day
  • consume >5 portion of fruits and vegetables per day

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02524938

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Contact: Nora TS Alshammari
Contact: Emilie Combet, PhD

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United Kingdom
NHS Greater Glasgow and Clyde Recruiting
Glasgow, United Kingdom
University of Glasgow Recruiting
Glasgow, United Kingdom
Sponsors and Collaborators
NHS Greater Glasgow and Clyde
University of Glasgow
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Principal Investigator: Emilie Combet, PhD University of Glasgow

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Responsible Party: NHS Greater Glasgow and Clyde Identifier: NCT02524938     History of Changes
Other Study ID Numbers: GN15DI242
First Posted: August 17, 2015    Key Record Dates
Last Update Posted: February 28, 2019
Last Verified: February 2019

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No

Keywords provided by NHS Greater Glasgow and Clyde:
Dietary polyphenols
Protein glycation

Additional relevant MeSH terms:
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Diabetes Mellitus
Diabetes Mellitus, Type 2
Renal Insufficiency
Renal Insufficiency, Chronic
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Kidney Diseases
Urologic Diseases