Reducing Dietary Acid With Food Versus Oral Alkali in People With Chronic Kidney Disease (ReDACKD)

Dylan MacKay

Status: Enrolling

Conditions: Chronic Kidney Diseases; Metabolic Acidosis

Treatments: Drug: Sodium bicarbonate; Dietary Supplement: Alkalizing Fruit and Vegetables

Study type: Interventional

Funder types: Other

Identifiers

NCT05113641

HS24768 (B2021:025)

Details and patient eligibility

About

Metabolic acidosis is a common problem that occurs with worsening chronic kidney disease. Dietary acid can build up when the kidneys are not working well. This can be associated with a higher risk of worsening kidney function and death. The usual treatment is a medication called sodium bicarbonate which works to balance the acids in the body. The medication however often does not work and causes side effects. Consumption of alkalizing fruit and vegetables may work as a treatment for metabolic acidosis. This trial is being done to see if fruit and vegetables, provided via home delivery, can become a viable management for metabolic acidosis in patients with chronic kidney disease.

Full description

Metabolic acidosis is a common complication of advanced chronic kidney disease (CKD). As kidney function declines, the ability to excrete excess dietary acid is reduced. This can lead to the development of metabolic acidosis, an imbalance in the body's acid-base balance. Metabolic acidosis is associated with a higher risk of CKD progression and mortality. Typical treatment includes an oral alkali, such as sodium citrate or sodium bicarbonate. Recent studies have shown that the treatment of metabolic acidosis can reduce the decline in kidney function and potentially prevent progression of CKD to dialysis. Treatment rates with an oral alkali are low because the treatments are ineffective, often poorly tolerated, and may be associated with net harm. Base producing fruit and vegetables are a potential treatment of metabolic acidosis by reducing the dietary contribution to overall acid load that must be managed by the kidneys. A recent systematic review and meta-analysis of clinical trials using oral alkali supplements or reduction in dietary acid intake using fruits and vegetables, when compared to no treatment, usual care or placebo found that these treatments increased serum bicarbonate and slowed the decline of kidney function. Fruit and vegetables are an effective and well-tolerated therapy for the treatment of metabolic acidosis in CKD. While oral alkali therapy has known adverse effects, important limitations also exist in the widespread applicability of fruit and vegetables as a treatment for metabolic acidosis. Only 2 single center randomized trials have examined the efficacy of fruit and vegetables for the management for acidosis. This dual-center trial will be the first randomized trial in Canada to evaluate the feasibility of providing fruit and vegetables via home delivery to patients for the management of metabolic acidosis in CKD. This study will be critical in designing a pan-Canadian phase 3 trial testing the efficacy of alkalizing fruit and vegetable provision on slowing the progression of CKD.

Enrollment: 40 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Participant is willing and able to give informed consent for participation in the trial
• Male or Female, aged 18 years or above
• Participants who have an eGFR between 15 and 40 ml/min/1.73m2
• Two consecutive measurements of serum bicarbonate of 14 to 22 mEq/L
• Systolic and diastolic blood pressure <160/100 mmHg
• Serum potassium <5.3 mmol/L
• Hemoglobin A1c below ≤ 11%
• Are registered in the nephrology clinic in Winnipeg or Halifax
• Participants are able to communicate in English and provide written informed consent

Exclusion criteria

• Anuria, dialysis or acute kidney injury/acute kidney failure in the 3 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 GI issues
• Participants who have participated in another research trial involving an investigational product in the past 12 weeks
• Currently on potassium binding therapy
• Female participant who is pregnant or on lactating

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

---

40 participants in 2 patient groups

Alkalizing Fruit and Vegetables

Experimental group

Description:

Participants randomized to fruit and vegetables (F+V) will receive weekly supplementation of alkalizing fruits and vegetables via home delivery in a box format. Participants will receive a 1-hour dietary counseling session from a registered dietitian (RD), following randomization, 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 F+V into the participant's current diet. Intervention will last 12 months.

Treatment:

Dietary Supplement: Alkalizing Fruit and Vegetables

Sodium Bicarbonate

Active Comparator group

Description:

Participants randomized to the alkali therapy will receive oral sodium bicarbonate 500mg tablets three times a day, reflecting a common starting dose at clinical practice. Thereafter, decisions around dose titration for the sodium bicarbonate will then be transferred to the participant's nephrologist who will be responsible for monitoring the participants serum bicarbonate concentration with a goal of maintaining a serum bicarbonate level \>22 mEq/L. Participants will receive counselling from a registered dietician (RD) as part of the standard care. Intervention will last 12 months.

Treatment:

Drug: Sodium bicarbonate