Biocompatible peritoneal dialysis solutions: do they indeed affect the outcome?

Numerous studies have confirmed beneficial effects of polyglucose dialysis solution (PG-DS), an amino acid dialysis solution (AA-DS), and bicarbonate (bic) or bicarbonate/lactate (bic/lac) buffered solutions on selected components of peritoneal bioavailability or clinical parameters of peritoneal dialysis (PD) patients. Few adverse effects have also been described. A question arises whether these solutions affect the PD outcome. A better controlled fluid status of PD patients associated with the use of PG-DS has been shown in a double-blind randomized controlled trial. Continuous cyclic PD patients treated with the PG-DS did not show changes in solute kinetics and peritoneal membrane markers remained unaltered. The use of PG-DS in anuric automated PD patients was associated with less impaired membrane function. A prospective, randomized, controlled study on the AA-DS in malnourished continuous ambulatory PD patients did not show significant effects of the AA-DS on patient survival, hospitalization rate, C-reactive protein levels, total urea Kt/V, ultrafiltration and drop-out rates, but nutritional status improved or was stable. Improved acid-base balance with bic-buffered solutions was shown in patients treated with automated PD or continuous PD. A registry-based study suggests better survival of patients treated with a neutral pH, low glucose degradation product solution, but there were no differences in dialysis technique survival, peritonitis-free survival, or peritonitis rates. However, reduced peritonitis rate was also reported with the use of bic/lac solutions. Current concepts of PD solutions involve efforts to use fluids which combine the advantages of PG-DS, AA-DS and bic-buffered solutions. Large-scale studies should be continued to improve biocompatibility of peritoneal solutions and to establish their effect on the clinical outcome.