Dietary Potassium Liberalization in Pre-Dialysis Patients

Official title

Dietary Potassium Liberalization With Fruit and Vegetables Versus Potassium Restriction in People With Chronic Kidney Disease (DK-Lib CKD) Trial

Overview

The study will look at the impact of the potassium content in fruits and vegetables, on serum potassium concentrations in people with Chronic Kidney Disease (CKD) using a randomized crossover design. Participants will receive home delivery of fruit and vegetables with either higher or lower potassium content in a random order. Clinical chemistry markers from blood and urine samples, blood pressure, physical functioning and health related quality of life will be assessed throughout the duration of the trial. This study will also measure their physical functioning, using a chair stand test. The results of this study could change the dietary recommendations for people with CKD related to potassium.

Detailed description

The kidney is a primary site of potassium regulation in the body. Hyperkalemia, elevated serum potassium, occurs in approximately 10% of patients with chronic kidney disease (CKD) and is associated with elevated all-cause mortality. To minimize the risk of hyperkalemia, individuals with CKD are told to restrict dietary potassium. This recommendation is based on very-low quality evidence. Dietary potassium restrictions can negatively impact quality of life, and may put participants at risk of nutritional deficiencies so they should be based on good quality evidence. There is a need for high quality randomized controlled trials investigating the impact of dietary potassium modification on serum potassium concentrations in people with CKD.

This trial will evaluate the impact and safety of dietary potassium liberalization using fruit and vegetables on serum potassium concentrations in people with CKD. In this 16-week study, the investigators will test if changing the amount of potassium people with CKD are eating with fruits and vegetables changes the amount of potassium in their blood. The investigators will do this by providing people with fruits and vegetables that are either high or low in potassium for a period of 6 weeks. Then these same participants will be provided with fruits and vegetables that they didn't receive in the first 6 weeks, for an additional 6 weeks in what is called a randomized crossover design. In a randomized crossover design everyone gets both treatments, but the order they get them in is chosen at random, like a coin toss. Thirty participants will be recruited to this study. The investigators will measure blood potassium during the study and see if it changes due to the change in potassium in the fruit and vegetables provided. The investigators think that changing the amount of potassium that participants eat through fruit and vegetables will not lead to a different level of potassium in the participants blood, and that having higher potassium fruit and vegetables in the diet may lead to an increase in the participants quality of life. This study's results could change the dietary recommendation given to people living CKD and potentially allow them to eat a greater variety of food.

Interventions

• Dietary supplement Liberalized dietary potassium via fruits and vegetables
  On the liberalized dietary potassium intervention, participants will receive groceries delivered to their houses that contain potassium rich fruit and vegetables, that contain more than 250 mg of potassium per typical serving. Participants will be instructed to incorporate the fruit and vegetables into their diet targeting a daily intake of 2000 mg of potassium a day from delivered fruit and vegetables, and a daily dietary potassium intake of 3500 mg.
• Dietary supplement Standard dietary potassium restriction
  Participants will receive weekly supplementation of lower potassium fruit and vegetables, that deliver less than 200 mg of potassium per typical serving. Participants will be instructed to incorporate the fruit and vegetables into their diet targeting a daily intake of 500 mg of K a day from the box, and a daily dietary K intake \< 2000 mg. Participants will receive counselling from a registered dietician (RD) to reinforce the potassium restriction.

Primary outcome measures

• Change in serum potassium concentrations between treatments [Time frame: between endpoints of each experimental period (week 8 to week 16)]

Secondary outcome measures (11)

• Change in physical function related quality of life between treatments [Time frame: between endpoints of each experimental period (week 8 to week 16)]
• Change in urinary potassium between treatments [Time frame: between endpoints of each experimental period (week 8 to week 16)]
• Change in urinary sodium between treatments [Time frame: between endpoints of each experimental period (week 8 to week 16)]
• Urinary albumin to creatinine Ratio [Time frame: between endpoints of each experimental period (week 8 to week 16)]
• Urinary urea [Time frame: between endpoints of each experimental period (week 8 to week 16)]
• Urinary phosphate [Time frame: between endpoints of each experimental period (week 8 to week 16)]
• Hemoglobin A1c [Time frame: between endpoints of each experimental period (week 8 to week 16)]
• Systolic blood pressure [Time frame: between endpoints of each experimental period (week 8 to week 16)]
• Diastolic blood pressure [Time frame: between endpoints of each experimental period (week 8 to week 16)]
• Five repetition chair stand time [Time frame: between endpoints of each experimental period (week 8 to week 16)]
• Dietary Intake [Time frame: between endpoints of each experimental period (week 8 to week 16)]

Eligibility criteria

Inclusion criteria

• Male or female, aged 18 years or above
• Participants who have an estimated glomerular filtration rate between 15 and 45 ml/min/1.73m2
• Serum potassium concentration between 4.5 and 5.5 milliequivalent (mEq)/L
• Hemoglobin A1c ≤ 11%
• Systolic and diastolic blood pressure \&lt;160/100 mmHg
• Are registered in the multidisciplinary nephrology clinic in Winnipeg
• Able to communicate in English and provide written informed consent

Exclusion criteria

• Serum potassium concentration \&gt; 5.6 mEq/L, anuria, dialysis, or acute kidney injury failure in the 6 months prior to screening
• Chronic obstructive pulmonary disease that requires the participant to be on oxygen
• New York Heart Association Class 3-4 Heart symptoms or heart, liver or renal transplant
• A myocardial infarction or stroke within the last 6 months
• Unable to consume study treatments or control, such as swallowing or gastro-intestinal issues
• Currently on potassium binding therapy
• In the opinion of the investigator any medical condition, uncontrolled systemic disease or concurrent illness that would decrease the study compliance or jeopardize the safety of the participant
• Female participant who is pregnant or lactating

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Crossover

Masking

Open label

Primary purpose

Treatment

Study locations

Canada · 2 centers

• Seven Oaks General Hospital Chronic Disease Innovation Centre — Winnipeg
• Health Sciences Centre — Winnipeg

Publications

• Iman Y, Balshaw R, Alexiuk M, Hingwala J, Cahill L, Mollard R, Tangri N, Mackay D. Dietary potassium liberalization with fruit and vegetables versus potassium restriction in people with chronic kidney disease (DK-Lib CKD): a clinical trial protocol. BMC Nephrol. 2023 Oct 13;24(1):301. doi: 10.1186/s12882-023-03354-4. PMID 37833679

Identifiers

NCT: NCT05090865 · HS25191 (B2021:104)

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗