Increasing transplantation incidence

Of the more than 500,000 patients on chronic dialysis in the US, less than one-fifth are active on the kidney transplant waiting list —despite broad agreement on the economic and quality-of-life benefits to transplant.^1-3 Several factors influence this, including graft availability, wait time, and post-transplant viability. 

Wait-list placement time and transplantation incidence

Most incident ESRD patients are prescribed conventional hemodialysis (IHD) over peritoneal dialysis (PD) in the United States.¹ This is despite findings that PD may be a better pre-transplant dialysis modality.⁴

• PD patients experienced a 32% reduction in wait time for placement on the transplant waiting list, an increased rate of being on the waiting list, and a shorter time to transplantation as compared to IHD patients.⁵
• Unadjusted transplant rates for incident PD patients has been reported as more than twofold higher than for HD patients.^5,6
• In a study of 620,020 IHD and 64,406 PD patients, adjusted transplant rates in PD were 30% to 60% higher relative to IHD.⁷

Influence of social support and dialysis adherence

Social support scores have been shown to be higher in PD than IHD patients and associated with better patient-centered outcomes—including greater patient satisfaction and health-related quality of life, increased transplantation, and reduced hospitalization.^8-11

• In a survey of 584 transplant providers, respondents were 1.68 times more likely to choose a profile of a transplant candidate who had social support, and 1.64 times more likely to choose one who always adheres to his/her medical regimen.¹²
• Nephrologists who offer explicit treatment recommendations and tailor discussions of suitable treatment options to patients were more influenced by adherence and quality of life than medical/surgical providers who were more influenced by candidates’ life expectancy with transplant.¹¹
• Social support was the most influential factor for providers concerned with avoiding organ waste, while least influential for clinicians concerned with fairness (p<0.05).¹¹

Delayed graft function and acute rejection

A few studies have shown lower incidence of delayed graft function after kidney transplantation in PD patients compared with IHD patients.^13-15 Factors involved may include patient fluid status and residual kidney function at the time of transplantation. 

• Pre-transplant PD use was associated with improved fluid status and a 36% lower risk of delayed graft function risk compared to pre-transplant IHD.¹⁶
• A recent study showed a 14% improvement in 5-year survival and a trend of lower acute rejection rate in use of PD compared to IHD before transplantation.¹⁷

Pre-transplant PD impact on weight, mortality risk, and post-transplant diabetes

Volume overload remains a greater problem for PD patients than for those on IHD.¹⁸ Body weight reduction post-transplant has been shown to be significantly higher with PD compared to IHD, indicating increased fluid overload in PD patients prior to transplantation.¹⁶

• Even with pre-transplant IHD support to improve volume status, PD patients still showed a 5% extracellular fluid volume excess before transplantation.¹⁶
• Despite difficulties in achieving dry weight, use of PD prior to transplantation had a 43% lower adjusted all-cause and 66% lower cardiovascular death compared to use of IHD.¹⁶
• Results of pre-transplant PD use and graph failure are mixed. Confounding by residual selection bias cannot be ruled out and merits further investigation.¹⁹
  • In a recent study, pre-transplant PD has been associated with 17% lower unadjusted death-censored graft failure.¹⁹
  • In contrast, in an analysis using a propensity score-matching algorithm in IHD vs. PD patients before transplantation, PD patients experienced similar graft loss.¹⁹
• Pre-transplantation use of PD has also been shown to significantly increase the risk of post-transplant diabetes mellitus development.²⁰

Conclusion

Evidence indicates that pre-transplantation use of PD positively affects post-transplantation outcomes. Transplantation incidence, transplantation rate, and post-transplantation graft function have been shown to be better in patients who used PD pre-transplantation compared to IHD. However, fluid management during PD is crucial and transplant-provider bias could be an obstacle to transplant candidacy. Patients should be informed of the benefits and risks of PD as applied to transplant outcomes.