Effect of Alkali Therapy on Vascular and Graft Function in Kidney Transplant Recipients

May 28, 2025 updated by: University of Colorado, Denver

Effect of Alkali Therapy on Vascular and Graft Function in Kidney Transplant

Lower serum bicarbonate levels, even within the normal laboratory range, in kidney transplant recipients (KTRs) are associated with an increased risk of graft loss, cardiovascular events and mortality. Because acid retention is common in KTRs, it is plausible that alkali therapy in KTRs may also result in improved vascular and graft function. The investigators will perform a randomized, double-blinded, placebo-controlled, 12 month study in 120 KTRs to examine the effect of sodium bicarbonate therapy on surrogate markers of CVD and graft function. The overall hypothesis is that treatment with bicarbonate will improve indicators of vascular and graft function in KTRs by decreasing complement activation.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
120

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 18-80 years
  • Serum bicarbonate 16-24 mEq/L on 2 separate measurements (at least 1 day apart)
  • Kidney transplant received 1 year prior to randomization
  • eGFR ≥ 45 ml/min/1.73m2 by CKD-EPI equation
  • Blood pressure <130/80 mm Hg prior to randomization
  • BMI < 40 kg/m2 (FMD measurements can be inaccurate in severely obese patients).
  • Able to provide consent
  • Immunosuppression regimen consisting of tacrolimus, mycophenolate mofetil and prednisone (95% of patients at University of Colorado are on this regimen)
  • Stable immunosuppression regimen for at least three months 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
  • Nephrotic range proteinuria (urine complement activation fragment measurements may not be accurate with severe proteinuria)
  • 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
  • Use of anticoagulants

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Sodium bicarbonate
Oral sodium bicarbonate at a dose of 0.5 mEq/kg-lean body weight/day
Drug: Sodium bicarbonate
Oral sodium bicarbonate at 0.5 mEq/kg-lean body weight/day
Placebo Comparator: Placebo
Oral placebo at a dose of 0.5 mEq/kg-lean body weight/day
Drug: Placebo
Placebo at 0.5 mEq/kg-lean body weight/day

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in Brachial artery flow mediated dilation at 12 months
Time Frame: Baseline and 12 months
Brachial artery FMD will be determined using high-resolution ultrasonographyECG-gated end-diastolic ultrasound images and Doppler flow of the brachial artery will be acquired during baseline and FMD conditions. For FMD, reactive hyperemia will be produced by inflating a pediatric BP cuff around the forearm to 250 mmHg for 5 minutes followed by rapid deflation.
Baseline and 12 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in Large elastic artery stiffness and compliance at 12 months
Time Frame: Baseline and 12 months
transcutaneous custom tonometers (Noninvasive hemodynamics Workstation, Cardiovascular Engineering Inc., Norwood, MA) will be positioned at the aorta and femoral artery to measure aortic pulse wave velocity.
Baseline and 12 months
Change in Tubular atrophy at 12 months
Time Frame: Baseline and 12 months
Kidney transplant biopsies will be performed. Morphometric analysis will be performed using trichrome and Sirius Red to determine tubular atrophy. All imaging will be done using an Aperio scanner.
Baseline and 12 months
Change in participant plasma and urine complement activation fragment levels at 12 months
Time Frame: Baseline and 12 months
Complement activation fragments (Ba, C4a, C3a, C5a, sC5b-9) will be measured at the University of Colorado Exsera Biolab located on the Anschutz Medical Campus.
Baseline and 12 months
Change in interstitial fibrosis at 12 months
Time Frame: Baseline and 12 months.
Kidney transplant biopsies will be performed. Morphometric analysis will be performed using trichrome and Sirius Red to determine interstitial fibrosis.
Baseline and 12 months.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Colorado, Denver

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Jessica Kendrick, MD MPH, University of Colorado Denver | Anschutz

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2021

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 31, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 14, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 10, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 16, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 29, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 28, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 21-3447
  • R01DK130255 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

At the conclusion of the study, data, which has been stripped of all personal identification information and coded with a number, will be made available to qualified individuals within the scientific community who apply for data use. The results and outcomes of this study will be made generally available by publication and journal articles submitted to PubMed Central in compliance with NIH access guidelines.

IPD Sharing Time Frame

At the conclusion of the study, data, which has been stripped of all personal identification information and coded with a number, will be made available to qualified individuals within the scientific community who apply for data use. The results and outcomes of this study will be made generally available by publication and journal articles submitted to PubMed Central in compliance with NIH access guidelines.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

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.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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