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Bicarbonate Administration in Kidney Transplant Recipients

Primary Purpose

Kidney Transplant; Complications, Metabolic Acidosis

Status
Completed
Phase
Not Applicable
Locations
United States
Study Type
Interventional
Intervention
Sodium Bicarbonate
Placebo
Sponsored by
University of Colorado, Denver
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional treatment trial for Kidney Transplant; Complications

Eligibility Criteria

18 Years - undefined (Adult, Older Adult)All SexesDoes not accept healthy volunteers

Inclusion Criteria:

  • Age ≥ 18 years
  • Kidney transplant received at least 1 year ago
  • Serum bicarbonate 20-26 mEq/L on 2 separate measurements (at least 1 day apart)
  • eGFR >45 ml/min/1.73m2
  • Blood pressure <140/90 mm Hg prior to randomization
  • BMI < 40 kg/m2 (FMD measurements can be inaccurate in severely obese patients).
  • Able to provide consent
  • Stable kidney transplant medication regimen for at least 1 month prior to randomization
  • Stable anti-hypertensive regimen for at least one month prior to randomization
  • Not taking medications that interact with agents administered during experimental sessions (e.g. sildenafil interacts with nitroglycerin).

Exclusion Criteria:

  • Significant comorbid conditions that lead the investigator to conclude that life expectancy is less than 1 year
  • Use of chronic daily oral alkali within the last 3 months (including sodium bicarbonate, calcium carbonate or baking soda)
  • Uncontrolled hypertension
  • Serum potassium < 3.3 or ≥ 5.5 mEq/L at screening
  • New York Heart Association Class 3 or 4 heart failure symptoms, known EF ≤30%, or hospital admission for heart failure within the past 3 months · Factors judged to limit adherence to interventions
  • Current participation in another research study
  • Pregnancy or planning to become pregnant or currently breastfeeding
  • Chronic use of supplemental oxygen

Sites / Locations

  • University of Colorado Hospital

Arms of the Study

Arm 1

Arm 2

Arm Type

Experimental

Placebo Comparator

Arm Label

Sodium bicarbonate

Placebo

Arm Description

During the treatment period, participants will receive 0.5 mEq/kg-lean body weight (LBW)/day of oral sodium bicarbonate for 8 weeks.

During the control period, participants will take the same number of placebo capsules as if they were assigned 0.5 mEq/kg-LBW/day of sodium bicarbonate.

Outcomes

Primary Outcome Measures

Change in Brachial Artery Flow-Mediated Dilation
Brachial artery Flow-Mediated Dilation (FMD) will be determined using high-resolution ultrasonography (Toshiba Xario 200) as described originally by Celermajer et al., and more recently by our group. FMD will be measured at the beginning and end of each study period for a total of 4 measurements. ECG-gated end-diastolic ultrasound images and Doppler flow of the brachial artery will be acquired during baseline and FMD conditions.

Secondary Outcome Measures

Change in Transforming Growth Factor Beta 1 (TGF-B1)
Urinary TGF-B1 will be measured from 24-hour urine collections. It will be measured by a commercially available ELISA (R&D Systems). The within day precision for this assay is 6.7% at 257 pg/ml. All measurements will be performed at the Children's Pediatric CTRC at Children's Hospital Colorado.
Change in Cognitive Function
Cognitive function will be assessed using the National Institutes of Health (NIH) Toolbox computerized tests to evaluate 1) attention, 2) episodic memory, 3) working memory, 4) language, 5) executive function, and 6) processing speed.

Full Information

First Posted
January 29, 2018
Last Updated
October 19, 2020
Sponsor
University of Colorado, Denver
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1. Study Identification

Unique Protocol Identification Number
NCT03428464
Brief Title
Bicarbonate Administration in Kidney Transplant Recipients
Official Title
Bicarbonate Administration in Kidney Transplant Recipients
Study Type
Interventional

2. Study Status

Record Verification Date
October 2020
Overall Recruitment Status
Completed
Study Start Date
December 5, 2018 (Actual)
Primary Completion Date
March 25, 2020 (Actual)
Study Completion Date
March 25, 2020 (Actual)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Sponsor
Name of the Sponsor
University of Colorado, Denver

4. Oversight

Studies a U.S. FDA-regulated Drug Product
No
Studies a U.S. FDA-regulated Device Product
No
Product Manufactured in and Exported from the U.S.
Yes

5. Study Description

Brief Summary
Metabolic acidosis is associated with vascular endothelial dysfunction and is a common complication in patients who have received a kidney transplant. Kidney transplant recipients (KTR) with lower serum bicarbonate levels, even within the normal range, have an increased risk of graft loss and mortality. The investigators propose a prospective, double-blind, randomized, placebo-controlled, 18-week crossover pilot study to examine the effects of sodium bicarbonate on vascular endothelial function, graft function, and cognitive function in 20 KTR patients.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Kidney Transplant; Complications, Metabolic Acidosis

7. Study Design

Primary Purpose
Treatment
Study Phase
Not Applicable
Interventional Study Model
Crossover Assignment
Masking
ParticipantCare ProviderInvestigatorOutcomes Assessor
Allocation
Randomized
Enrollment
20 (Actual)

8. Arms, Groups, and Interventions

Arm Title
Sodium bicarbonate
Arm Type
Experimental
Arm Description
During the treatment period, participants will receive 0.5 mEq/kg-lean body weight (LBW)/day of oral sodium bicarbonate for 8 weeks.
Arm Title
Placebo
Arm Type
Placebo Comparator
Arm Description
During the control period, participants will take the same number of placebo capsules as if they were assigned 0.5 mEq/kg-LBW/day of sodium bicarbonate.
Intervention Type
Drug
Intervention Name(s)
Sodium Bicarbonate
Other Intervention Name(s)
Baking soda
Intervention Description
Participants will take ½ the daily dose of sodium bicarbonate in the morning and the other ½ in the evening.
Intervention Type
Other
Intervention Name(s)
Placebo
Intervention Description
Participants will take ½ the daily dose of a placebo in the morning and the other ½ in the evening.
Primary Outcome Measure Information:
Title
Change in Brachial Artery Flow-Mediated Dilation
Description
Brachial artery Flow-Mediated Dilation (FMD) will be determined using high-resolution ultrasonography (Toshiba Xario 200) as described originally by Celermajer et al., and more recently by our group. FMD will be measured at the beginning and end of each study period for a total of 4 measurements. ECG-gated end-diastolic ultrasound images and Doppler flow of the brachial artery will be acquired during baseline and FMD conditions.
Time Frame
Baseline, 8, 10, and 18 weeks
Secondary Outcome Measure Information:
Title
Change in Transforming Growth Factor Beta 1 (TGF-B1)
Description
Urinary TGF-B1 will be measured from 24-hour urine collections. It will be measured by a commercially available ELISA (R&D Systems). The within day precision for this assay is 6.7% at 257 pg/ml. All measurements will be performed at the Children's Pediatric CTRC at Children's Hospital Colorado.
Time Frame
Baseline, 8, 10, and 18 weeks
Title
Change in Cognitive Function
Description
Cognitive function will be assessed using the National Institutes of Health (NIH) Toolbox computerized tests to evaluate 1) attention, 2) episodic memory, 3) working memory, 4) language, 5) executive function, and 6) processing speed.
Time Frame
Baseline, 8, 10, and 18 weeks

10. Eligibility

Sex
All
Minimum Age & Unit of Time
18 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Inclusion Criteria: Age ≥ 18 years Kidney transplant received at least 1 year ago Serum bicarbonate 20-26 mEq/L on 2 separate measurements (at least 1 day apart) eGFR >45 ml/min/1.73m2 Blood pressure <140/90 mm Hg prior to randomization BMI < 40 kg/m2 (FMD measurements can be inaccurate in severely obese patients). Able to provide consent Stable kidney transplant medication regimen for at least 1 month prior to randomization Stable anti-hypertensive regimen for at least one month prior to randomization Not taking medications that interact with agents administered during experimental sessions (e.g. sildenafil interacts with nitroglycerin). Exclusion Criteria: Significant comorbid conditions that lead the investigator to conclude that life expectancy is less than 1 year Use of chronic daily oral alkali within the last 3 months (including sodium bicarbonate, calcium carbonate or baking soda) Uncontrolled hypertension Serum potassium < 3.3 or ≥ 5.5 mEq/L at screening New York Heart Association Class 3 or 4 heart failure symptoms, known EF ≤30%, or hospital admission for heart failure within the past 3 months · Factors judged to limit adherence to interventions Current participation in another research study Pregnancy or planning to become pregnant or currently breastfeeding Chronic use of supplemental oxygen
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Jessica Kendrick, MD MPH
Organizational Affiliation
University of Colorado, Denver
Official's Role
Principal Investigator
Facility Information:
Facility Name
University of Colorado Hospital
City
Aurora
State/Province
Colorado
ZIP/Postal Code
80045
Country
United States

12. IPD Sharing Statement

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Bicarbonate Administration in Kidney Transplant Recipients

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