Background: Scaling glomerular filtration rate (GFR) to body surface area (BSA) has been widely accepted, and was debated in recent years. Although the indexation ability of BSA is inferior to other physiological variables, the evaluation of BSA formulae is still meaningful to clinical practice. In this study, to evaluate the indexation ability of BSA formulae, the repeated measures analyses of camera-based scintigraphy (Gates method, gGFR) and plasma-based clearance (pGFR) were used to specially focus on the between-subject variability that tried to be minimized by GFR normalization.
Methods: The patients, who were older than 18 y and suffered from renal diseases, were enrolled and grouped according to the Chinese BMI (body mass index) criteria. All patients accepted renal scintigraphy and plasma clearance examinations. The gGFR and pGFR were separately scaled to DuBois & DuBois, Boyd, Stevenson, Gehan, Haycock, Mosteller, Hu and Livingston and Lee's formula. In the repeated measures analyses, the intraclass correlation coefficient (ICC), concordance correlation coefficient (CCC) and the ratio of residual standard deviation to pooled standard deviation (RSD/PSD) were used for the evaluation.
Results: During January 2010 and May 2012, 220 patients were enrolled. The evaluated BSA formulae had well correlated results and significant differences among BMI groups. From high to low, the sequence of the correlation between BMI and BSA formula was L-L, Haycock, Gehan, Boyd, Mosteller, Stevenson, Hu and DuBois & DuBois formula. Both the scaled indices (ICC and CCC) and RSD/PSD indicated that, the sequence of indexation ability of BSA equations was Livingston < Haycock < Gehan < Stevenson < Mosteller < Boyd < Hu < DuBois & DuBois.
Conclusions: Among the evaluated BSA formulae, DuBois & DuBois formula correlates to BMI the worst, and has the best indexation ability in scaling GFR of adult renal patients.