Reproducibility of serial creatinine excretion measurements in peritoneal dialysis

Table 3 Creatinine excretion in patients with three studies

Variable	1st clearance study	2nd clearance study	3rd clearance study	P value
PD duration, mo	8.6 ± 7.8	16.8 ± 11.6	24.7 ± 16.3
VU, L/24-h	0.58 ± 0.66	0.45 ± 0.59	0.38 ± 0.50	0.0001
VD, L/24-h	11.5 ± 4.0	11.8 ± 3.7	12.4 ± 3.7	NS
Kt/V urea, weekly	2.28 ± 0.65	2.14 ± 0.58	2.12 ± 0.63	0.0245
CCr, L/1.73 m2, weekly	79.3 ± 35.6	71.4 ± 27.8	68.0 ± 26.9	0.0335
SUN, mg/dL	50.4 ± 18.5	49.5 ± 17.9	49.2 ± 19.2	NS
[Cr]S, mg/dL	9.5 ± 3.5	9.8 ± 3.4	10.1 ± 3.3	0.0066
EXCr U, mg/24-h	418 ± 404	370 ± 425	286 ± 362	< 0.0001
EXCr D, mg/24-h	731 ± 379	767 ± 396	779 ± 382	NS1
EXCr T, mg/24-h	1149 ± 416	1137 ± 454	1065 ± 442	0.0087

¹Statistical trend (P = 0.0895). 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.