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Understanding the Urine Electrolyte Profile of the Individual Renal Unit

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ClinicalTrials.gov Identifier: NCT02837393
Recruitment Status : Terminated (Low Recruitment and Enrollment)
First Posted : July 19, 2016
Last Update Posted : August 18, 2017
Sponsor:
Information provided by (Responsible Party):
Johns Hopkins University

Brief Summary:
The investigators objective is to determine if urinary electrolyte abnormalities exist in only one or both kidneys in participants with and without a history of kidney stones. To meet this objective, the investigators are going to take urine samples from each kidney at the time of kidney stone surgery. The samples will then be analyzed for absolute and relative differences in the concentrations of urine electrolytes, such as calcium.

Condition or disease Intervention/treatment
Kidney Calculi Nephrolithiasis Urolithiasis Procedure: Ureteral catheterization

Detailed Description:

Nephrolithiasis is common within the general population. Although the majority of patients with a symptomatic stone event will not require surgical intervention, the rate of recurrence is high. Therefore, reducing this rate of recurrence is important.

Traditionally, this has been achieved with a combination of serum and urine metabolic evaluation followed by targeted medication and dietary interventions. Specifically, it is recommended that a single 24-hour urine collection for analysis of urine electrolytes be performed. A 24-hour urine collection is bladder urine, which is pooled urine from both kidneys. The urine is then analyzed for the relative and absolute concentrations of electrolytes and small molecules known to be associated with stone formation. These include creatinine, calcium, citrate, oxalate, potassium, magnesium, phosphate, uric acid, and urate.

When an abnormality is detected on a 24-hour urine collection the assumption is that this is due to a global metabolic defect present in both kidneys. However, this may not be the case. It is possible there could be a relative imbalance with both kidneys having a defect, but to different degrees (or different defects in one or multiple electrolytes). It is also possible that one kidney has a dominant defect, but the contralateral kidney is normal, and therefore the 24-hour urine collection would only represent the dominant kidney with the defect. Finally, it is possible that the converse is true. One kidney has no defect, but the contralateral kidney has a minor defect. In this example, the 24-hour urine collection would appear normal as the dominant normal kidney masks the minor defect. This concept of differential kidney electrolyte handling was previously described in children. Therefore, understanding individual kidney metabolic profiles is important.

The purpose of the investigators' study will be to (1) characterize the urine electrolyte profile of each individual renal unit; (2) identify participants who have differences between their renal unit urine electrolyte profiles, and their renal units and bladder urine electrolyte profiles; and (3) correlate differences in renal unit urine electrolyte profiles with clinical manifestations of kidney stones, such as stone formation or growth. By characterizing individual renal unit urine electrolyte profiles, the investigators' may be able to isolate a phenotype of stone formers who would not otherwise be identified with traditional 24-hour urine collection. The investigators' can then target this phenotype in future investigations with dietary and medication interventions to hopefully prevent future stone events.

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Study Type : Observational
Actual Enrollment : 13 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Understanding the Urine Electrolyte Profile of the Individual Renal Unit
Study Start Date : July 2016
Actual Primary Completion Date : April 1, 2017
Actual Study Completion Date : April 1, 2017

Resource links provided by the National Library of Medicine


Group/Cohort Intervention/treatment
History of Kidney Stones
Participants with a history of kidney stones who will be undergoing kidney surgery.
Procedure: Ureteral catheterization
During ureteral catheterization, urine samples will be obtain from each kidney

No History of Kidney Stones
Participants without a history of kidney stones who will be undergoing kidney surgery.
Procedure: Ureteral catheterization
During ureteral catheterization, urine samples will be obtain from each kidney




Primary Outcome Measures :
  1. Concentrations of urine electrolytes [ Time Frame: 1 year ]
    The investigators' will determine if there is a difference in urine electrolyte concentrations within individuals between the two kidneys, and across individuals in those with and without a history of kidney stones.


Biospecimen Retention:   Samples Without DNA
Urine


Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
The study will be a prospective cohort study conducted within the Department of Urology at Johns Hopkins Hospital and Bayview Medical Center. The study population will be comprised of a convenience sample of participants 18 years of age or older who will be undergoing upper urinary tract surgery as part of routine clinical care for a diagnosis of nephrolithiasis, hematuria, ureteral stricture, ureteropelvic junction obstruction, hydronephrosis, or intra-operative identification of the ureters.
Criteria

Inclusion Criteria:

  1. Age ≥18 years of age
  2. Planed upper urinary tract surgery for a diagnosis of nephrolithiasis, hematuria, ureteral stricture, ureteropelvic junction obstruction, hydronephrosis, or intra-operative identification of the ureters.

Exclusion Criteria:

  1. History of an anatomic abnormality of the urinary tract.
  2. History of a solitary kidney.
  3. Untreated or a history of lower or upper urinary tract urothelial malignancy.
  4. Active urinary tract infection.
  5. Pregnancy.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02837393


Locations
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United States, Maryland
Johns Hopkins Hospital
Baltimore, Maryland, United States, 21287
Sponsors and Collaborators
Johns Hopkins University
Investigators
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Principal Investigator: Justin B Ziemba, MD Johns Hopkins School of Medicine
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Responsible Party: Johns Hopkins University
ClinicalTrials.gov Identifier: NCT02837393    
Other Study ID Numbers: IRB00099408
First Posted: July 19, 2016    Key Record Dates
Last Update Posted: August 18, 2017
Last Verified: August 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Additional relevant MeSH terms:
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Urolithiasis
Nephrolithiasis
Kidney Calculi
Calculi
Pathological Conditions, Anatomical
Urologic Diseases
Kidney Diseases
Urinary Calculi