# Pretransplant Serum Creatinine in Peritoneal Dialysis Patients Predicts Graft Outcomes

## TL;DR

Higher pretransplant creatinine levels in peritoneal dialysis patients are linked to worse kidney transplant outcomes, suggesting a potentially treatable risk factor.

## Contribution

First study to show pretransplant serum creatinine predicts graft outcomes in peritoneal dialysis patients.

## Key findings

- Elevated pretransplant creatinine (>12 mg/dL) increases risk of death-censored graft loss and delayed graft function.
- Higher creatinine risk is more pronounced in older patients and those with longer dialysis history.
- No association found between pretransplant creatinine and all-cause graft loss.

## Abstract

Although peritoneal dialysis (PD) as a pretransplant dialysis modality is associated with favorable outcomes after kidney transplant, it is unknown if pretransplant serum creatinine (Scr) level is associated with subsequent graft outcomes in candidates managed with PD. Our objective was to examine the association between Scr at the time of transplant and short-term and long-term outcomes posttransplant.

Retrospective cohort study.

A total of 20,166 adult (≥18 years of age) patients who were receiving PD at the time of a first living or deceased donor kidney transplant in the United States between 2000 and 2017, identified using the Scientific Registry of Transplant Recipients database.

Primary exposure was final Scr level before transplant, categorized as <5, 5-8, 8-12, and >12 mg/dL. Sensitivity analyses for patient subgroups included recipient age (≥50 vs <50 years) and dialysis vintage (≥3 vs <3 years) at transplant.

The primary outcome was death-censored graft loss (DCGL). Secondary outcomes included all-cause graft loss and delayed graft function (DGF).

Pretransplant Scr was significantly associated with DCGL (adjusted HR, 1.17; 95% CI, 1.02-1.34 for Scr >12 mg/dL [reference <5 mg/dL]) and DGF (adjusted OR, 2.71; 95% CI, 2.26-3.26 for Scr >12 mg/dL [reference <5 mg/dL]). There was no association with all-cause graft loss. The risk of DCGL and DGF associated with high pretransplant Scr was higher for those who were older (≥50 years) and those with longer dialysis vintage (≥3 years).

No access to potential predictors of pretransplant Scr including residual kidney function, dialysis adequacy and adherence; exact timing of Scr values pretransplant was unknown.

To our knowledge, this is the first study to explore the association between pretransplant Scr level in PD patients and graft outcomes after kidney transplantation. The reason for this increased risk is unclear but may reflect reduced residual kidney function, among other factors.

Kidney transplantation is a life-saving procedure and is associated with improved survival for people living with kidney failure. However, kidney transplants may fail during the lifetime of transplant recipients. Identifying treatable factors that contribute to kidney transplant failure before transplantation is important. Many of these factors relate to dialysis before transplantation. Therefore, our study examined whether creatinine level before transplantation in peritoneal dialysis patients influences transplant survival. Our study of more than 20,000 patients from the United States found that peritoneal dialysis patients with elevated pretransplant creatinine levels have a significantly higher risk of transplant loss. This finding is important because it identifies high creatinine as a predictor and potentially treatable factor that contributes to kidney transplant failure.