The importance of residual renal function in peritoneal dialysis.

BACKGROUND

Peritoneal dialysis (PD) patients with preserved residual diuresis have a lower risk of death and complications. Here we analyzed associations between residual diuresis and presence of fluid overload and biomarkers of cardiac strain and nutrition in PD patients.

METHODS

Among 44 PD patients placed into three subgroups, depending on volume of residual diuresis (group A ≤ 500; group B 600-1900; and group C ≥ 2000 mL/day), we examined: overhydration (OH) assessed by bioimpedance analysis (BIA; yielding OH index OHBIA) and by clinical criteria (edema and hypertension); nutritional status (by subjective global assessment, SGA); metabolic status (electrolytes, serum lipid profile, CRP, and albumin); biomarkers of fluid overload and cardiac strain (N-terminal probrain natriuretic peptide, NT-proBNP, and troponin T, TnT); and, echocardiography and chest X-ray.

RESULTS

With increasing residual diuresis in group A, B and C, fewer patients had signs of overhydration defined as OHBIA > 1.1 L (75.0, 42.9 and 33.3 %) or peripheral edema (25.0, 21.4 and 0 %) and NT-proBNP (15199 ± 16150 vs. 5930 ± 9256 vs. 2600 ± 3907 pg/mL; p < 0.05) and TnT (0.15 ± 0.17 vs. 0.07 ± 0.09 vs. 0.04 ± 0.03 ng/mL; p < 0.05) were significantly lower. Significant differences were found also in ejection fraction, SGA, and total cholesterol, albumin and hemoglobin levels whereas blood pressures and serum CRP did not differ significantly.

CONCLUSION

Signs of OH and cardiac strain are common in PD patients, even in those with diuresis of 1000-2000 mL/day and with no clinical signs or symptoms, suggesting that even moderate decrease in residual renal function in PD patients associate with OH and other complications.