The effect of low glucose degradation product, neutral pH versus standard peritoneal dialysis solutions on peritoneal membrane function: the balANZ trial

Abstract

Background: The balANZ trial recently reported that neutral pH, low glucose degradation product (biocompatible) peritoneal dialysis (PD) solutions significantly delayed anuria and reduced peritonitis rates compared with conventional solutions. This article reports a secondary outcome analysis of the balANZ trial with respect to peritoneal membrane function.

Methods: Adult, incident PD patients with residual renal function were randomized to receive either biocompatible or conventional (control) PD solutions for 2 years. Peritoneal equilibration tests were performed at 1, 6, 12, 18 and 24 months. Peritoneal small solute clearances and ultra-filtration (UF) were measured at 3, 6, 9, 12, 18 and 24 months.

Results: Of the 185 patients recruited into the trial, 85 patients in the Balance group and 82 patients in the control group had peritoneal membrane function evaluated. Mean 4-h dialysate:plasma creatinine ratios (D:P Cr 4h) at 1 month were significantly higher in the Balance group compared with controls (0.67 ± 0.10 versus 0.62 ± 0.10, P = 0.002). Over the 2-year study period, mean D:P Cr 4 h measurements remained stable in the Balance group but increased significantly in controls [difference -0.004 per month, 95% confidence interval (95% CI) -0.005 to -0.002, P < 0.001]. Similar results were obtained for dialysate glucose ratios (D/D0 glucose). Peritoneal UF was significantly lower in the Balance group than in controls at 3 and 6 months. Over the 2-year study period, peritoneal UF increased significantly in the Balance group but remained stable in controls (difference 24 mL/day/month, 95% CI 9-39, P = 0.002). No differences in peritoneal small solute clearances, prescribed dialysate fill volumes or peritoneal glucose exposure were observed between the two groups.

Conclusions: Biocompatible and conventional PD solutions exert differential effects on peritoneal small solute transport rate and UF over time. Adequately powered trials assessing the impact of these differential membrane effects on PD technique and patient survival rates are warranted.

Fig. 1.

Change in D:P Cr 4 h over time in the balance (A) and control (B) groups over 2 years. Grey lines represent individual patient measurements while solid lines represent predicted gradients. The difference in gradients between the two groups was statistically significant (P < 0.001).

Fig. 2.

Change in D/D0 glucose over time in the Balance (A) and control (B) groups over 2 years. Grey lines represent individual patient measurements while solid lines represent predicted gradients. The difference in gradients between the two groups was statistically significant (P < 0.01).

Fig. 3.

Change in peritoneal CpCr over time in the Balance (A) and control (B) groups over 2 years. Grey lines represent individual patient measurements while solid lines represent predicted gradients. The difference in gradients between the two groups was not statistically significant (P = 0.69).

Fig. 4.

Change in peritoneal CpUr over time in the Balance (A) and control (B) groups over 2 years. Grey lines represent individual patient measurements while solid lines represent predicted gradients. The difference in gradients between the two groups was not statistically significant (P = 0.45).

Fig. 5.

Change in peritoneal UF over time in the Balance (A) and control (B) groups over 2 years. Grey lines represent individual patient measurements while solid lines represent predicted gradients. The difference in gradients between the two groups was statistically significant (P = 0.002).

Fig. 6.

Change in peritoneal UF, normalized for peritoneal glucose exposure, over time in the Balance (A) and control (B) groups over 2 years. Grey lines represent individual patient measurements while solid lines represent predicted gradients. The difference in gradients between the two groups was statistically significant (P = 0.004).