Biocompatible dialysis fluids for peritoneal dialysis

Peritoneal dialysis (PD) is a form of treatment for people with advanced kidney disease to an extent where their own kidney function is inadequate to meet the body's requirements. PD is flexible, and allows for therapy to be instituted by patients at home. After initial surgical insertion of a catheter into the abdomen, patients are required to perform regular exchange of PD solution at a prescribed rate to allow clearance of toxins and fluids across the peritoneal membrane. Unfortunately, the longevity of PD is limited, which is largely due to peritoneal membrane injury that results from the use of biologically 'unfriendly' PD solutions. The 'unfriendly' characteristics of these solutions include high glucose levels, glucose breakdown products and acidity. To overcome these hurdles, biocompatible PD solutions (i.e. neutral pH, lowered levels of glucose breakdown products, use of materials alternative to glucose such as icodextrin) have been manufactured that are designed to cause less damage to the peritoneal membrane. This review of interventions testing the benefits and harms of biocompatible PD solutions identified 36 studies (2719 patients).

When compared to conventional PD solutions, we found that neutral pH, low glucose breakdown product PD solution resulted in better preservation of patient's own kidney function including urine output (7 studies, 520 patients), with on average 126.39 mL greater urine output per day. Patients who received glucose polymer (icodextrin) PD solutions were 70% less likely to experience uncontrolled episodes of fluid overload (2 studies, 100 patients).

No significant harms with their use were reported by 10 studies. Many of the studies were of small size, short follow-up duration, poor quality, and had inconsistent reporting of outcomes. Further studies within this area are needed.

Authors' conclusions: 

Based on generally sub-optimal quality studies, use of neutral pH, low GDP PD solution led to greater urine output and higher residual renal function after use exceeded 12 months. Icodextrin prescription improved peritoneal ultrafiltration and mitigated uncontrolled fluid overload. There were no significant effects on peritonitis, technique survival, patient survival or harms identified with their use. Based on the best available evidence, the use of these 'biocompatible' PD solutions resulted in clinically relevant benefits without added risks of harm.

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Background: 

The longevity of peritoneal dialysis (PD) is limited by high rates of technique failure, some of which stem from peritoneal membrane injury. 'Biocompatible' PD solutions have been developed to reduce damage to the peritoneal membrane.

Objectives: 

This review aimed to look at the benefits and harms of biocompatible PD solutions in comparison to standard PD solutions in patients receiving PD.

Search strategy: 

We searched the Cochrane Renal Group's Specialised Register (28 February 2013), through contact with the Trials Search Co-ordinator using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE and EMBASE, and handsearching conference proceedings.

Selection criteria: 

All randomised controlled trials (RCTs) and quasi-RCTs in adults and children comparing the effects of biocompatible PD solutions (neutral pH, lactate-buffered, low glucose degradation product (GDP); neutral pH, bicarbonate (± lactate)-buffered, low GDP; glucose polymer (icodextrin)) in PD were included. Studies of amino acid-based PD solutions were excluded.

Data collection and analysis: 

Two authors extracted data on study quality and outcomes (including adverse effects). The authors contacted investigators to obtain missing information. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for categorical variables, and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous variables.

Main results: 

Thirty-six eligible studies (2719 patients) were identified: Neutral pH, lactate-buffered/bicarbonate (± lactate)-buffered, low GDP PD solution (24); icodextrin (12). Allocation methods and concealment were generally incompletely reported, and adequate in only ten studies (27.8%). Patients lost to follow-up ranged from 0% to 83.4%.

Neutral pH, low GDP versus conventional glucose PD solution

Based on generally sub-optimal quality evidence, the use of neutral pH, low GDP PD solutions was associated with larger urine volumes at the end of the studies, up to three years of therapy duration (7 studies, 520 patients: MD 126.39 mL/d, 95% CI 26.73 to 226.05). Improved preservation of residual renal function was evident in studies with greater than 12 month follow-up (6 studies, 360 patients: SMD 0.31, 95% CI 0.10 to 0.52). There was no significant effect on peritonitis, technique failure or adverse events with the use of neutral pH, low GDP PD solutions.

Glucose polymer (icodextrin) versus conventional glucose PD solution

There was a significant reduction in episodes of uncontrolled fluid overload (2 studies, 100 patients: RR 0.30, 95% CI 0.15 to 0.59) and improvement in peritoneal ultrafiltration (4 studies, 102 patients, MD 448.54 mL/d, 95% CI 289.28 to 607.80) without compromising residual renal function (4 studies, 114 patients: SMD 0.12, 95% CI -0.26 to 0.49) or urine output (3 studies, 69 patients: MD -88.88 mL/d, 95% CI -356.88 to 179.12) with icodextrin use. A comparable incidence of adverse events with the icodextrin (four studies) was reported.

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