Dietary Potassium Liberalization in Pre-Dialysis Patients (DK-LIB)

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

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.

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 6 weeks. Then these same participants will be provided with fruits and vegetables that they didn't receive in the first 6 weeks, for 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.

Participants will receive weekly supplementation of higher potassium fruit and vegetables via grocery home delivery during the liberalized dietary potassium 2-week run-in and liberalized potassium treatment period, then cross-over to the restricted potassium treatment period following a 2-week washout period. Participants will receive a 30-60 minute dietary counseling session in the first week of each treatment period from a registered dietitian (RD), either in person or via videoconference, depending on regional Coronavirus disease (COVID)-19 restrictions and participant preference, which will outline the concepts of the dietary intervention. The RD will also recommend the best ways to prepare and include the fruit and vegetables into the participant's current diet.

Participants will receive weekly supplementation of higher potassium fruit and vegetables via grocery home delivery during the liberalized dietary potassium 2 week run-in and then start receiving a restricted potassium treatment period, then cross-over to the liberalized potassium treatment period following a 2-week washout period. Participants will receive a 30-60 minute dietary counseling session in the first week of each treatment period from a registered dietitian (RD), either in person or via videoconference, depending on regional COVID-19 restrictions and participant preference, which will outline the concepts of the dietary intervention. The RD will also recommend the best ways to prepare and include the fruit and vegetables into the participant's current diet

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 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 1500 mg of potassium a day from delivered fruit and vegetables, and a daily dietary potassium intake of 3500 mg.

Participants will receive weekly supplementation of lower potassium fruit and vegetables, that deliver less than 125 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.

Serum potassium at the end of the liberalize dietary potassium period compared to the end of restricted dietary potassium period

Participants will complete the SF-12 physical component score of the Kidney Disease Quality of Life Short Form (KDQOL-SF) questionnaire.

calculated by dividing urinary albumin concentration in milligrams by urinary creatinine concentration in grams

Blood pressure will be measured in triplicate using a validated blood pressure monitor following Kidney Disease: Improving Global Outcomes (KDIGO) 2021 measurement guidelines, the average of the 2nd and 3rd measurements will be recorded.

Blood pressure will be measured in triplicate using a validated blood pressure monitor following KDIGO 2021 measurement guidelines, the average of the 2nd and 3rd measurements will be recorded.

Assessing physical functionality by asking participant to sit with arms folded in a chair and then stand up and sit down 5 times as fast as they can, time to complete is recorded.

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 4.9 and 5.5 milliequivalent (mEq)/L Hemoglobin A1c < 11% Are registered in the multidisciplinary nephrology clinic in Winnipeg Able to communicate in English and provide written informed consent Exclusion Criteria: Serum potassium concentration > 5.4 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 failure 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

De-identified individual participant data (IPD)may be placed in a repository if required by a journal for publication purposes. De-identified IPD may also be requested from the principle investigator.