Reproducibility of serial creatinine excretion measurements in peritoneal dialysis

Table 4 Creatinine excretion in patients with four clearance studies

Variable	1st clearance study	2nd clearance study	3rd clearance study	4th clearance study	P value
PD duration, mo	8.1 ± 12.6	16.5 ± 4.4	24.5 ± 16.3	31.9 ± 16.8
VU, L/24-h	0.54 ± 0.55	0.41 ± 0.49	0.33 ± 0.40	0.29 ± 0.42	< 0.0001
VD, L/24-h	11.8 ± 3.9	12.2 ± 3.6	12.2 ± 3.5	12.5 ± 3.2	NS
Kt/V urea, weekly	2.27 ± 0.65	2.15 ± 0.56	2.13 ± 0.54	2.10 ± 0.55	0.0356
CCr, L/1.73 m2, weekly	77.5 ± 29.7	70.4 ± 28.5	68.5 ± 25.7	66.1 ± 22.1	0.0238
SUN, mg/dL	49.8 ± 16.7	49.5 ± 15.4	49.2 ± 15.3	49.0 ± 13.5	NS
[Cr]S, mg/dL	9.8 ± 3.6	10.2 ± 3.7	10.8 ± 3.8	10.8 ± 3.6	0.0009
EXCr U, mg/24-h	411 ± 438	382 ± 460	272 ± 345	282 ± 481	0.0011
EXCr D, mg/24-h	755 ± 406	788 ± 424	808 ± 438	853 ± 398	0.0021
EXCr T, mg/24-h	1166 ± 440	1170 ± 495	1080 ± 455	1135 ± 521	NS

PD: Peritoneal dialysis; NS: Not significant; VU: Urine volume; VD: Drained volume of spent dialysate; Kt/V urea: Fractional urea clearance, weekly; C_Cr: Weekly renal plus peritoneal creatinine clearance; SUN: Serum urea nitrogen; [Cr]_S: Serum creatinine concentration; EX_Cr D: Creatinine excretion in spent dialysate; EX_Cr U: Creatinine excretion in urine; EX_Cr T: Total creatinine excretion in urine plus dialysate.