Determining eligibility for lung transplantation: A nationwide assessment of the cutoff glomerular filtration rate

Abstract

Background: Historical concerns about lung transplantation in patients with a glomerular filtration rate (GFR) ≤ 50 ml/min/1.73 m(2) have not been validated. We hypothesize that a pre-transplant GFR ≤ 50 ml/min/1.73 m(2) represents a high mortality risk, especially in the setting of acute GFR decline. In addition, we explore the potential for improved risk stratification using a statistically derivable alternative cutoff.

Methods: Adult, primary, lung recipients in the United Network for Organ Sharing database were analyzed (October 1987 to December 2011). Recursive partitioning identified the GFR value that provides maximal separation in 1-year mortality. Survival over/under the cutoffs was compared using stratified log-rank, Cox, and Kaplan-Meier methods, before and after 1:2 propensity score matching.

Results: Median GFR at time of transplant for 19,425 study patients was 94.2 ml/min/1.73 m(2) (quartile 1-quartile, 2 76.9-105.9 ml/min/1.73 m(2)). Recursive partitioning identified a GFR of 40.2 ml/min/1.73 m(2) as the ideal inflection point for predicting 1-year survival. Cutoffs demonstrated statistically significant effects on survival after 840 patients with a GFR ≤ 50 ml/min/1.73 m(2) (hazard ratio, 1.28; 95% confidence interval, 1.15-1.43) and 401 patients with a GFR ≤ 40.2 ml/min/1.73 m(2) (hazard ratio, 1.57; 95% confidence interval, 1.36-1.83) were matched with high GFR controls (p < 0.001). In 13,509 patients with available GFR at the time of listing and transplant, a pre-transplant GFR decline of ≥ 50% from baseline was associated with worse survival (p < 0.001).

Conclusions: A pre-transplant GFR ≤ 50 ml/min/1.73 m(2) is associated with decreased survival. However, patients with GFR between 40 and 50 ml/min/1.73 m(2) do not suffer excessive post-transplant mortality and should not be automatically excluded from listing. Notably, outcomes are worse in patients with poor renal function and concomitant pre-transplant GFR decline. Strategies should be devised to detect and manage interval renal deterioration before lung transplantation.

Keywords: GFR cutoff; GFR threshold; Lung transplantation; renal function.