Renal Function Assessment in the Elderly Using Plasma Creatinine Assay and Lean Body Mass Measurement

Summary

Glomerular filtration rate (GFR) is the recommended parameter to assess renal function. The reference technique to measure GFR (clearance of a glomerular agent) is not commonly used. Instead, estimations (eGFR) are routinely taken from serum creatinine (SCr) with several published formulae: Cockcroft and Gault, MDRD, CKD-EPI. Basically, all these formulae aim at predicting the endogenous creatinine production by morphological parameters (age, body weight...) However, in the elderly, muscular mass is extremely variable and sarcopenia is quite commonly encountered (frequently linked to Alzheimer disease). This is probably the main reason why the aforementioned formulae are not valid in this population: for a given renal function, a lower muscular mass induces a lower creatinine production and, henceforth, a lower SCr value, which gives an overestimation of eGFR.

Muscular mass is closely linked to lean body mass (LBM), which can be properly assessed by whole-body dual X-ray absorptiometry (DXA). Alternatively, Bioelectric Impedance Spectroscopy (BIS) can also be used.

Investigators postulate that it is possible to estimate GFR in the elderly from both SCr and LBM estimation from DXA. Proof of concept has already been made by others but until now, no specific formula for the elderly has been devised and properly validated.

Investigators'aim is thus to propose a new formula to predict GFR from both SCr and LBM (estimated from DXA) in the elderly. This formula will be elaborated from a first series of 100 patients and validated on a second series of 100 other patients.

Conditions

• Renal Function

Interventions

OTHER

measurement of morphological parameters

measurement of morphological parameters : thigh perimeter, leg perimeter, arm perimeter.

BIOLOGICAL

a blood sample

One single blood sample to assay SCr (enzymatic), BUN (blood urea nitrogen), cystatin C, CRP, Na, K, Cl, albuminemia.

BIOLOGICAL

albumin or blood in urine

dipstick analysis for albumin or blood in urine

DEVICE

Dual X-ray absorptiometry (DXA)

measurement of lean body mass by whole-body DXA

DEVICE

Bioelectric Impedance Spectroscopy (BIS)

measurement of lean body mass by BIS

BIOLOGICAL

51Cr-EDTA plasma clearance

measurement of 51Cr-EDTA plasma clearance to determine GFR

Sponsors & Collaborators

• University Hospital, Strasbourg, France

  lead OTHER

Study Design

Allocation

NA

Purpose

OTHER

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

75 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2014-11-03

Primary Completion

2022-11-02

Completion

2022-11-02

Countries

• France

Study Locations