Glomerular filtration rate can be accurately predicted using lean mass measured by dual-energy X-ray absorptiometry.
BACKGROUND
Accurate assessment of renal function is important in the management of patients with kidney disease yet is often difficult to obtain. Formulae, designed for clinical use, have been developed to predict glomerular filtration rate (GFR) utilizing serum creatinine (Scr). Additional parameters are included in these formulae to account for variations in Scr due to differences in total body lean mass in kg (LM). Therefore, the purpose of this study was to derive a simple formula to predict GFR based on Scr and direct quantification of LM.


METHODS
Ten subjects with a wide range of renal function had GFRs determined by [125I]iothalamate clearance and LM determined by dual-energy X-ray absorptiometry as well as fasting measurements of Scr, serum and 24 h urine urea nitrogen, and albumin.


RESULTS
The following formula was derived using LM (kg) and Scr (mg/dl): predicted GFR=(2.4xLM)-(0.75xLMxScr). The correlation coefficient for this formula was 0.97, when compared with [125I]iothalamate clearances, and similar to the MDRD formulae (R=0.87-0.95).


CONCLUSIONS
Although further validation is necessary, these findings suggest that total body non-invasive measurement of LM along with Scr can be used to accurately predict GFR.
Taylor
Timothy P
TP
Department of Medicine, Medical University of South Carolina, Charleston, SC, USA.
Wang
Wei
W
Shrayyef
M Zakarea
MZ
Cheek
DeAnna
D
Hutchison
Florence N
FN
Gadegbeku
Crystal A
CA
D015502:Absorptiometry, Photon; D000328:Adult; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index