# Selection Patterns and Outcomes of Kidney Transplantation Versus Dialysis in Lung Recipients with End-Stage Renal Disease: A Single-Center Retrospective-Observational Study

## TL;DR

This study compares kidney transplantation and dialysis in lung transplant patients with kidney failure, showing better survival for transplant recipients but highlighting the role of selection bias.

## Contribution

The study introduces a Clinical Selection Score and evaluates outcomes in a rare patient population with ESRD following lung transplantation.

## Key findings

- Kidney transplant recipients had significantly lower mortality compared to dialysis patients.
- The Clinical Selection Score effectively distinguished between transplant and dialysis candidates.
- Living donors were available for nearly all transplant recipients but none for dialysis patients.

## Abstract

Background: End-stage renal disease (ESRD) affects up to 25% of lung transplant recipients within 10 years. The selection process for kidney transplantation versus dialysis reflects complex clinical decision-making that has not been systematically characterized. Methods: This retrospective observational study analyzed all lung transplant recipients who developed ESRD at our center from 2010 to 2024 (n=32), comparing those receiving kidney transplantation (n = 18) versus those remaining on dialysis (n = 14). We developed an exploratory Clinical Selection Score to retrospectively characterize observed selection patterns and calculated E-values to assess robustness to unmeasured confounding. Results: Kidney transplant recipients were younger (35.7 ± 12.9 vs. 48.4 ± 14.8 years, p = 0.013) with better selection characteristics quantified by our Clinical Selection Score (4.1 ± 0.8 vs. 1.6 ± 1.1 points, p < 0.001). The score showed excellent discrimination (C-statistic 0.82). Living donors were available for 88.9% of transplanted patients versus 0% of dialysis patients. In our selected cohorts, mortality was 22.2% in kidney transplant recipients vs. 78.6% in dialysis patients (p = 0.002), with median survival of 161.6 vs. 126.6 months (p = 0.021). After adjustment for age, kidney transplantation was observed to be associated with 72% lower mortality risk (HR 0.28, 95% CI 0.09–0.89, p = 0.031), though selection bias limits causal interpretation. The E-value of 6.61 suggests robustness to unmeasured confounding. Conclusions: This observational study describes real-world selection patterns and their associated outcomes in lung transplant recipients with ESRD. While carefully selected patients receiving kidney transplantation experienced favorable results, many patients were appropriately managed with dialysis based on medical and non-medical factors. Our analysis provides transparency about selection criteria and outcomes to inform clinical decision-making. Larger multicenter studies are needed to validate these findings and develop prediction tools.