FIGURE 1:

Effects of the choice of GFR indexing measure on the relationship between gender and serum urea nitrogen in the CRIC cohort. Serum urea nitrogen versus: (A) eGFR, (B) iGFR indexed to weight, (C) iGFR indexed to BSA, (D) iGFR indexed to TBW, (E) iGFR indexed to REE and (F) iGFR indexed to LBM. Loess-smoothed plots are shown. (For comparison of the effects of gender across the respective ranges of excretory function, curves versus indexed iothalamate GFR for women are truncated with exclusion of three outlying high GFR datapoints). iGFR, iothalamate GFR; BSA, estimated body surface area; TBW, estimated total body water; REE, estimated resting energy expenditure; LBM, estimated lean body mass.