Acute kidney injury increases mortality after lung transplantation

Background: Acute kidney injury requiring renal replacement therapy (RRT) is associated with increased mortality after cardiac surgery. Studies examining the impact of RRT after lung transplantation (LTx) are limited. We evaluated risk factors and outcomes associated with RRT after LTx.

Methods: We retrospectively reviewed all LTx recipients in the United Network for Organ Sharing database. Preoperative renal function was stratified by glomerular filtration rate (GFR) as determined by the Modification of Diet in Renal Disease formula (strata: ≥90, 60 to 90, and <60 mL · min(-1) · 1.73 m(-2)). Primary outcomes were 30-day, 1-year, and 5-year survival and need for post-LTx RRT. Risk adjusted multivariable Cox proportional hazards regression examined mortality. A multivariable logistic regression model evaluated risk factors for RRT.

Results: From 2001 to 2011, 12,108 patients underwent LTx. After LTx, 655 patients (5.51%) required RRT. Patients requiring post-LTx RRT had decreased survival at 30 days (96.7% versus 76.0%, p < 0.001), 1 year (85.5% versus 35.8%, p < 0.001), and 5 years (56.4% versus 20.0%, p < 0.001). These differences persisted on multivariable analysis at 30 days (hazard ratio [HR] 7.98 [6.16 to 10.33], p < 0.001), 1 year (HR 7.93 [6.84 to 9.19], p < 0.001), and 5 years (HR 5.39 [4.75 to 6.11], p < 0.001). Preoperative kidney function was an important predictor of post-LTx RRT for a GFR of 60 to 90 (odds ratio 1.42 [1.16 to 1.75], p = 0.001) and a GFR less than 60 (odds ratio 2.68 [2.07 to 3.46], p < 0.001]. High center volume was protective.

Conclusions: In the largest study to evaluate acute kidney injury after LTx, the incidence of RRT is 5.51%. The need for post-LTx RRT dramatically increases both short- and long-term mortality. Several variables, including preoperative renal function, are predictors of post-LTx RRT and could be used to identify transplant candidates at risk for acute kidney injury.