Determination of Kidney Function

Sponsor

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) (NIH)

Overall Status

Terminated

CT.gov ID

NCT00001978

Collaborator

(none)

456

Enrollment

Location

371.7

Actual Duration (Months)

1.2

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Much more about kidney disorders can be learned by determining kidney function. This research proposes to study the kidneys function by several parameters known as glomerular filtration rate (GFR), Renal Plasma Flow (RPF), and Glomerular Capillary Wall Permselectivity.

The study will select patients suffering from different types of kidney diseases. These patients will be selected based on the presence of significant amounts of protein in their urine (proteinuria).

Standard blood and urine tests are often unable to provide completely accurate information about the kidney. In order for researchers to have a more accurate idea of kidney function, they will use alternative tests. Test materials (para aminohippurate and inulin) will be injected into patients veins that provides information based on their filtration through the kidneys....

Condition or Disease	Intervention/Treatment	Phase
Kidney Disease Proteinuria Autoimmune / Connective Tissue Diseases

Detailed Description

The study of various kidney disorders will be facilitated by determinations of true glomerular filtration rate and/or effective renal plasma flow employing inulin or non-radioactive iothalamate and/or para aminohippurate (PAH), respectively.

Selected patients with proteinuria will be asked to participate in studies of glomerular capillary wall permselectivity calculated from the fractional clearances of the endogenous proteins, albumin and IgG and from the fractional clearances of polydisperse neutral dextran with effective molecular radii ranging from 20-60 angstroms. To achieve this, low molecular weight dextran will be administered by slow IV injection immediately following the inulin or iothalamate and/or PAH priming doses.

Glomerular filtration rate, effective renal plasma flow and/or glomerular permselectivity can be measured simultaneously during a standard hydrated urinary clearance study. Timed urine and blood collections will be obtained, typically requiring a total of 60 to 90 minutes. The total test time, including pre-test hydration, is 4 to 5 hours.

Alternatively, glomerular filtration rate can be measured by one of two plasma clearance methods that do not require urine collections. For one method, a steady-state plasma concentration of iothalamate will be achieved in ambulatory patients by a 24-hour subcutaneous infusion of iothalamate using an insulin pump. For the second method, the decline in plasma concentration of iothalamate will be measured after an intravenous dose of iothalamate.

Study Design

Study Type:

Observational

Actual Enrollment :

456 participants

Observational Model:

Cohort

Time Perspective:

Prospective

Official Title:

Determination of Glomerular Filtration Rate, Effective Renal Plasma Flow and Glomerular Capillary Wall Permselectivity

Actual Study Start Date :

Oct 11, 1989

Actual Primary Completion Date :

Oct 2, 2020

Actual Study Completion Date :

Oct 2, 2020

Arms and Interventions

Arm	Intervention/Treatment
Study Cohort Selected patients with proteinuria

Outcome Measures

Primary Outcome Measures

Glomerular filtration rate [4-5 hours]
Glomerular filtration rate, effective renal plasma flow and /or glomerular permselectivity can be measured simultaneously during astandard hydrated urinary clearance study. Timed urine and blood collections will be obtained, typically requiring a total of 60 to 90 minutes. The total test time, including pretest hydration, is 4 to 5 hours.

Secondary Outcome Measures

Effective renal plasma flow []
Glomerular filtration rate, effective renal plasma flow and /or glomerular permselectivity can be measured simultaneously during astandard hydrated urinary clearance study. Timed urine and blood collections will be obtained, typically requiring a total of 60 to 90 minutes. The total test time, including pretest hydration, is 4 to 5 hours.

Eligibility Criteria

Criteria

Ages Eligible for Study:

7 Years and Older

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

INCLUSION CRITERIA:

Ability to provide informed assent to all aspects of the study after full information is provided.

An indication to measure kidney function as accurately as possible in the context of an approved clinical protocol within the intramural programs of the National Institutes of

Health:

For minor subjects, a clinical indication will be required.
For adult subjects, a clinical and/or research indication will be required.

EXCLUSION CRITERIA:

Pregnant females or nursing mothers will be excluded from all aspects of this study (at least until the infant is stable on a regimen of formula feeding).

Patients will not receive a test material if there is a history of allergy to that material.

Patients with a history of bronchial asthma or allergy to iodine-containing contrast material will not receive iothalamate.