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

NCT ID: NCT05113641

Last Updated: 2025-10-01

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 40 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-08-04
• Study Completion Date: 2026-09-30

Brief Summary

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.

Detailed 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.

Conditions

Chronic Kidney Diseases; Metabolic Acidosis

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Alkalizing Fruit and Vegetables

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.

Group Type: EXPERIMENTAL

Alkalizing Fruit and Vegetables

Intervention Type: DIETARY_SUPPLEMENT

The weekly deliveries will contain combinations of fresh, frozen, and dried fruits and vegetables, as well as juices and soups which have been selected for their negative potential renal acid load (PRAL) values and shelf-life. All participants will be started at a F+V intake equal to -30 to -40 mEq per day reduction in dietary acid load estimated by the PRAL equation. Participants serum bicarbonate concentration will be measured at 1 month, and at 3 months, those with values \< 22 mEq/L will have their recommended amount of F+V increased to -40 to -50 mEq per day. If a participant's 1- or 3-month serum bicarbonate value exceeds 29 mEq/L, their target dose of F+V in mEq/d will be reduced by 25%.

Sodium Bicarbonate

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.

Group Type: ACTIVE_COMPARATOR

Sodium bicarbonate

Intervention Type: DRUG

Study nephrologist will prescribe the oral alkali therapy (sodium bicarbonate) and the medications will be dispensed by the dispensed by the clinic/hospital pharmacies.

Interventions

Alkalizing Fruit and Vegetables

The weekly deliveries will contain combinations of fresh, frozen, and dried fruits and vegetables, as well as juices and soups which have been selected for their negative potential renal acid load (PRAL) values and shelf-life. All participants will be started at a F+V intake equal to -30 to -40 mEq per day reduction in dietary acid load estimated by the PRAL equation. Participants serum bicarbonate concentration will be measured at 1 month, and at 3 months, those with values \< 22 mEq/L will have their recommended amount of F+V increased to -40 to -50 mEq per day. If a participant's 1- or 3-month serum bicarbonate value exceeds 29 mEq/L, their target dose of F+V in mEq/d will be reduced by 25%.

Intervention Type: DIETARY_SUPPLEMENT

Sodium bicarbonate

Study nephrologist will prescribe the oral alkali therapy (sodium bicarbonate) and the medications will be dispensed by the dispensed by the clinic/hospital pharmacies.

Intervention Type: DRUG

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Dalhousie University

OTHER

Sponsor Role: collaborator

Mount Saint Vincent University

OTHER

Sponsor Role: collaborator

Dylan MacKay

OTHER

Sponsor Role: lead

Responsible Party

Dylan MacKay

Assistant Professor

Responsibility Role: SPONSOR_INVESTIGATOR

Principal Investigators

Navdeep Tangri, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Seven Oaks General Hospital Chronic Disease Innovation Centre

Dylan MacKay, PhD

Role: PRINCIPAL_INVESTIGATOR

George and Fay Yee Centre for Healthcare Innovation

Karthik Tennankore, MD

Role: PRINCIPAL_INVESTIGATOR

Nova Scotia Health Authority

Locations

Seven Oaks General Hospital Chronic Disease Innovation Centre

Winnipeg, Manitoba, Canada

Site Status: RECRUITING

Health Sciences Center

Winnipeg, Manitoba, Canada

Site Status: RECRUITING

Chronic Kidney Disease (Renal) ClinicQEII - Dickson Building

Halifax, Nova Scotia, Canada

Site Status: ACTIVE_NOT_RECRUITING

Countries

Canada

Central Contacts

Rebecca Mollard, PhD

Role: CONTACT

rmollard@sogh.mb.ca

204-631-3834

Facility Contacts

Navdeep Tangri, MD, PhD

Role: primary

ntangri@sogh.mb.ca

204-631-3834

Jay Hingwala, MD

Role: primary

jhingwala@hsc.mb.ca

204-787-3863

References

Mollard R, Cachero K, Luhovyy B, Martin H, Moisiuk S, Mahboobi S, Balshaw R, Collister D, Cahill L, Tennankore KK, Tangri N, MacKay D. Reducing Dietary Acid With Fruit and Vegetables Versus Oral Alkali in People With Chronic Kidney Disease (ReDACKD): A Clinical Research Protocol. Can J Kidney Health Dis. 2023 Aug 7;10:20543581231190180. doi: 10.1177/20543581231190180. eCollection 2023.

Reference Type: DERIVED

PMID: 37560749 (View on PubMed)

Other Identifiers

HS24768 (B2021:025)

Identifier Type: -

Identifier Source: org_study_id