Background. Residual renal function (RRF) impacts outcome of peritoneal dialysis (PD) patients. Some PD fluids contain glucose degradation products (GDPs) which have been shown to affect cell systems and tissues. They may also act as precursors of advanced glycosylation endproducts (AGEs) both locally and systemically, potentially inflicting damage to the kidney as the major organ for AGE elimination. We conducted a clinical study in PD patients to see if the content of GDP in the PD fluid has any influence on the decline of the residual renal function.
Methods. In a multicentre approach, 80 patients (GFF ≥ 3 mL/min/1.732 or creatinine clearance ≥3 mL/min/1.73 m2) were randomized to treatment with a PD fluid containing low levels of GDP or standard PD fluid for 18 months. RRF was assessed every 4–6 weeks. Fluid balance, mesothelial cell mass marker CA125, peritoneal membrane characteristics, C-reactive protein (CRP), total protein, albumin, electrolytes and phosphate were measured repeatedly.
Results. Data from 69 patients revealed a significant difference in monthly RRF change: −1.5% (95% CI = −3.07% to +0.03%) with low GDP (43 patients) vs −4.3% (95% CI = −6.8% to −2.06%) with standard fluids (26 patients) (P = 0.0437), independent of angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker medication. Twenty-four-hour urine volume declined more slowly with low-GDP fluid compared to standard fluids (12 vs 38 mL/month, P = 0.0241), and monthly change of phosphate level was smaller (+0.013 vs +0.061 mg/dL, P = 0.0381).
Conclusions. Our prospective study demonstrates for the first time a significant benefit concerning preservation of RRF and urine volume of using a PD fluid with low GDP levels. These findings suggest that GDPs might affect patient outcome related to RRF.