Volume 59, Issue 3, Pages 1165-1174 (March 2001) Anthropometry-based equations overestimate the urea distribution volume in hemodialysis patients  Wybe D. Kloppenburg, Coen A. Stegeman, Paul E. De Jong, Roel M. Huisman  Kidney International  Volume 59, Issue 3, Pages 1165-1174 (March 2001) DOI: 10.1046/j.1523-1755.2001.0590031165.x Copyright © 2001 International Society of Nephrology Terms and Conditions

Figure 1 Bland-Altman plots of intermethod differences in urea distribution volume (UDV) values based on direct dialysis quantification (DDQ) and the Watson equations (WAT), a fixed proportion of postdialysis body weight (%BW) and skinfold thickness measurements (SFT). All three anthropometric methods overestimated UDVDDQ. The limits of agreement (LOA) were rather large. Symbols are: (•) males; (○) females. Kidney International 2001 59, 1165-1174DOI: (10.1046/j.1523-1755.2001.0590031165.x) Copyright © 2001 International Society of Nephrology Terms and Conditions

Figure 2 Variation between urea distribution volume (UDV) values based on direct dialysis quantification (DDQ) and a fixed proportion of postdialysis body weight (%BW) versus total body fat. The differences between UDV%BW and UDVDDQ are expressed as a percentage of UDVDDQ. The difference between UDV%BW and UDVDDQ correlated with the percentage of body fat, especially in males (total group, r = 0.57, P < 0.001; males, r = 0.63, P < 0.001; females, r = 0.45, P = 0.07). Symbols are: (•) males; (○) females. Kidney International 2001 59, 1165-1174DOI: (10.1046/j.1523-1755.2001.0590031165.x) Copyright © 2001 International Society of Nephrology Terms and Conditions

Figure 3 Boxplots of dietary protein intake (DPI) and protein equivalent of total nitrogen appearance (PNA) values using urea distribution volumes (UDVs) determined by direct dialysate quantitation (DDQ), Watson equations (WAT), fixed percentage of body weight (%BW) and skinfold thickness measurements (SFT). Anthropometric-based PNA values overestimated actual dietary protein. Shown are the 10th, 25th, 50th, 75th and 90th percentiles. *P < 0.001 vs. DPI; †P < 0.001 vs. PNADDQ; ‡P < 0.001 vs. PNAWAT and PNASFT. Kidney International 2001 59, 1165-1174DOI: (10.1046/j.1523-1755.2001.0590031165.x) Copyright © 2001 International Society of Nephrology Terms and Conditions

Figure 4 Bland-Altman plot of differences between protein equivalent of total nitrogen appearance determined by direct dialysate quantification (PNADDQ) and dietary protein intake (DPI). The agreement between PNADDQ and DPI varied considerably in individual hemodialysis patients. Symbols are: (•) males; (○) females. Kidney International 2001 59, 1165-1174DOI: (10.1046/j.1523-1755.2001.0590031165.x) Copyright © 2001 International Society of Nephrology Terms and Conditions