Effect of Urinary Alkalinization on Urine Uric Acid Precipitation and Crystallization in Adults With Type 1 Diabetes (Alk-UA)

January 14, 2022 updated by: University of Colorado, Denver

Effect of Urinary Alkalinization on Urine Uric Acid Precipitation and Crystallization in Adults With Type 1 DiabetesL a Open-label Trial

The purpose of this study is to determine whether alkalinization of urine uric acid by 2 doses of sodium bicarbonate (1950mg) over 24-hours reduces precipitation and crystallization of urine uric acid over in adults with type 1 diabetes.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Diabetic nephropathy is characterized not only by glomerular disease but also tubulointerstitial injury. The tubular changes associated with diabetic nephropathy, include basement membrane thickening, tubular hypertrophy, epithelial-mesenchymal transition, glycogen accumulation and interstitial inflammation. Although glomerular changes has received significantly more attention from researchers and clinicians than tubulointerstitial changes in diabetes, tubular injury is known to associate better with renal function than glomerular injury. In fact, tubular proteinuria may precede microalbuminuria with type 1 diabetes, suggesting that tubular damage may be induced earlier than glomerular injury in the course of diabetic nephropathy.

Serum uric acid (SUA) is lower in adolescents and adults with type 1 diabetes compared to non-diabetic peers. Despite lower levels SUA remains an important risk factor for diabetic nephropathy in type 1 diabetes, with a large clinical trial underway examining the ability of allopurinol to prevent early renal loss. Several mechanisms have been proposed to explain the lower levels of SUA in type 1 diabetes including glucosuria induced uricosuria leading to spilling of urine uric acid (UUA) and lowering of SUA, and the notion that intracellular uric acid (IUA) and/ or UUA rather than SUA may be responsible for the development of complications. Animal studies have demonstrated that blocking uric acid production protects the kidney from tubulointerstitial injury, which suggests a causal role for uric acid in the development of diabetic tubular injury. Relative dehydration, secondary to glucosuria, exercise or inadequate liquid intake, may lead to concentrated and acidic urine, which may cause UUA to precipitate and crystallize in type 1 diabetes. The UUA precipitation and crystallization is thought to induce inflammation and injury of the tubules with possible retrograde glomerular injury. Moreover, it was recently shown that UUA promoted apoptosis in human proximal tubular cells by oxidative stress and activation of NADPH Oxidase NOX 4.

Oral alkali replacements are readily available, safe and include the following formulations sodium bicarbonate, BiCitra (sodium citrate and citric acid), PolyCitra (citric acid, sodium citrate, and potassium citrate), polycitra-K (potassium citrate and citric acid). In contrast to sodium bicarbonate, citrate is converted to bicarbonate in the liver and thus this conversion is affected by liver disease. Usual adult doses for urinary alkalinization are 325 to 2000 mg orally 1 to 4 times a day. One gram provides 12 mEq (mmoL) each of sodium and bicarbonate, and is titrated to a goal of urine pH of 8.0. In a prospective open-label trial 4 g of sodium bicarbonate was administered orally 3 times daily to 9 healthy volunteers for 24 hours, and after 10 hours all participants had a urine pH ≥ 7 and after 20 hours all participants had urine pH ≥ 8. No adverse effects or abnormal blood results were documented during the 24-hour follow-up. Urinary alkalinization should solubilize UUA thereby increasing the concentration of uric acid in urine and decreasing precipitation and crystallization of UUA. It is unknown whether alkalinization of urine reduces UUA precipitation and crystallization in type 1 diabetes.

With diabetic nephropathy being the leading cause of end-stage renal disease in the Western world, it is critical to develop a better understanding of the determinants of risk and progression of early diabetic nephropathy, to improve outcomes in patients with type 1 diabetes. UUA is a particularly attractive therapeutic target due to the potential to reduce tubular injury with sodium bicarbonate. Accordingly, the investigators propose a pilot experimental study examining the effect of urine alkalinization with oral sodium bicarbonate on UUA precipitation and crystallization in adults with type 1 diabetes.

Study Type

Interventional

Enrollment (Actual)

45

Phase

  • 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 Locations

  • United States
    • Colorado
      • Aurora, Colorado, United States, 80045
        • Barbara Davis Center for Diabetes

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

Ages Eligible for Study

18 years to 45 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Adults (aged 18-45 years) with type 1 diabetes
  • Participants must be able to be fasting prior to study visit and give informed consent.

Exclusion Criteria:

  • Non-type 1 diabetes
  • History of eGFR <60 ml/min/1.73m2 or microalbuminuria or greater
  • History of hypocalcemia or at risk of hypocalcemia
  • Taking allopurinol or uric acid altering medications
  • Ketogenic diet
  • Ketonuria
  • Taking phosphorus binders (e.g. sevelamer)
  • Pregnant or breastfeeding
  • Taking the following medications which may interact with sodium bicarbonate (e.g. phentermine, pseudoephedrine, antifungal medication, cephalosporin antibiotics [e.g. Keflex], tetracycline antibiotics [e.g. doxycycline], steroids or lithium)
  • Taking SGLT-2 inhibitors
  • Taking blood pressure medications

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: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Sodium Bicarbonate
All participants will receive 2 doses of 1950mg Sodium Bicarbonate
Drug: sodium bicarbonate
All participants will receive 2 doses of 1950mg sodium bicarbonate
Other Names:
  • NaHCO3

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Urine Uric Acid Concentration (Increased Solubility) by Assay
Time Frame: Day 1 (pre-therapy) and Day 2 (post-therapy)
Urine uric acid were evaluated using a QuantiChrom UA kit assay (DIUA-250) with quantitative colorimetric UA determination at 590 nm (BioAssay System, California, USA).
Day 1 (pre-therapy) and Day 2 (post-therapy)
Change in Number of Participants With Urine Uric Acid Precipitation by Polarized Microscopy
Time Frame: Day 1 (pre-therapy) and Day 2 (post-therapy)
Urine uric acid crystals were identified by polarized microscopy (Polarized light imaging Zeiss Axiovert 135; 0.3NA objective), and pictures were captured from each urine sample. UA crystals were defined dichotomously as being present or absent.
Day 1 (pre-therapy) and Day 2 (post-therapy)

Collaborators and Investigators

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

Sponsor

University of Colorado, Denver

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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

January 1, 2017

Primary Completion (Actual)

July 1, 2017

Study Completion (Actual)

August 1, 2017

Study Registration Dates

First Submitted

July 16, 2015

First Submitted That Met QC Criteria

July 16, 2015

First Posted (Estimate)

July 20, 2015

Study Record Updates

Last Update Posted (Actual)

January 24, 2022

Last Update Submitted That Met QC Criteria

January 14, 2022

Last Verified

January 1, 2022

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 15-0541

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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