Quality of Life Assessments in Hemodialysis and Peritoneal Dialysis Patients: An Important Dimension of Patient Choice: Why Is the Evidence Favoring Hemodialysis over Peritoneal Dialysis Misleading?

The benefit of early survival on PD versus HD—Why this is (still) very important

There are a number of misconceptions around the identified early survival benefit of peritoneal dialysis (PD) relative to hemodialysis (HD), including that such benefits “even out in the end” since the relative risk of death over time eventually encompasses 1.0 (or even an estimate that is unfavorable to PD); that the early benefit is, in fact, most likely due to unmeasured confounding; and such benefits are only due to the influence of central venous catheters and “crash starters” in the HD group. In fact, the early survival benefit results in a substantial gain of patient life years in PD cohorts relative to HD ones, even if it the benefit appears to “even out in the end,” is relatively insensitive to unmeasured confounding, and persists even when the effects of central venous catheters are accounted for. In this review, the calculations and arguments are made to support these tenets. Survival on dialysis is still one of the most important considerations for all stakeholders in the end-stage kidney disease community, including patients who rank it among their top priorities. Shared decision-making is a fundamental patient right and requires both balanced information and an iterative mechanism for a consensual decision based on shared understanding and purpose. A cornerstone of this process should be an explicit discussion of the early survival benefit of PD relative to HD.

Gremlin promotes peritoneal membrane injury in an experimental mouse model and is associated with increased solute transport in peritoneal dialysis patients

The peritoneal membrane becomes damaged in patients on peritoneal dialysis (PD). Gremlin 1 (GREM1) inhibits bone morphogenic proteins (BMPs) and plays a role in kidney development and fibrosis. We evaluated the role of gremlin in peritoneal fibrosis and angiogenesis. In a cohort of 32 stable PD patients, GREM1 concentration in the peritoneal effluent correlated with measures of peritoneal membrane damage. AdGrem1, an adenovirus to overexpress gremlin in the mouse peritoneum, induced submesothelial thickening, fibrosis, and angiogenesis in C57BL/6 mice, which was associated with decreased expression of BMP4 and BMP7. There was evidence of mesothelial cell transition to a mesenchymal phenotype with increased α smooth muscle actin expression and suppression of E-cadherin. Some of the GREM1 effects may be reversed with recombinant BMP7 or a pan-specific transforming growth factor β (TGF-β) antibody. Neovascularization was not inhibited with a TGF-β antibody, suggesting a TGF-β-independent angiogenic mechanism. Swiss/Jackson Laboratory (SJL) mice, which are resistant to TGF-β-induced peritoneal fibrosis, responded in a similar fashion to AdGrem1 as did C57BL/6 mice with fibrosis, angiogenesis, and mesothelial-to-mesenchymal transition. GREM1 was associated with up-regulated TGF-β expression in both SJL and C57BL/6 mice, but SJL mice demonstrated a defective TGF-β-induced GREM1 expression. In summary, GREM1 induces fibrosis and angiogenesis in mouse peritoneum and is associated with increased solute transport in these PD patients.

Peritoneal dialysis patient selection: characteristics for success

This review focuses on the strategy of patient selection for peritoneal dialysis (PD) based on published epidemiology studies and observational data. With the success of the PD first model in Hong Kong, experience shows that there is no particular patient group that cannot be put on PD except those who have major problems in the abdomen. Incident patients should be offered the choice to receive PD at the start of dialysis in order to preserve better the residual renal function. Concern has also been expressed for a time-dependent negative impact of PD on survival, although PD in general provides survival advantage at least during the first few years after the start of dialysis. Regular patient review is essential to allow prompt adjustment of the dialysis regimen and modality when required. Accumulating research suggests that center size has a significant effect on the patient and technique survival of patients undergoing PD. Comorbid diabetes, large and small body size, peritoneal membrane transport status, elderly age group, and socioeconomic status are important patient factors to consider. Good clinical and psychosocial care of the PD patients are essential as well as the attention to their compliance. Enhanced training to medical and nursing personnel on PD is one of the key success factors for improving its utilization and outcome.