Severe acute kidney injury according to the RIFLE (risk, injury, failure, loss, end stage) criteria affects mortality in lung transplantation.

Background: The RIFLE criteria (risk, injury, failure, loss, end stage) are new consensus definitions for acute kidney injury (AKI) associated with increased mortality; however, they have not been applied in lung transplantation (LTx). Using the RIFLE criteria, we examined the effect of AKI on outcomes and cost in LTx.

Methods: We retrospectively reviewed all LTx patients at our institution since the lung allocation score (LAS) system was initiated (May 2005-August 2010). Using the Modification of Diet in Renal Disease formula, we assigned appropriate RIFLE class (R, I, F) comparing baseline creatinine to peak levels in the first 7 days after LTx. Generalized linear models assessed the effect of AKI on in-hospital and 1-year mortality. Hospital charges were used to examine the financial effect of AKI.

Results: During the study, 106 LTx were performed. Excluding patients bridged to LTx with extracorporeal membrane oxygenation, 84 (86%) lived 1 year. Median LAS was 37.1 (interquartile range, 34.1-45.2). RIFLE status was I or F in 39 (36.7%), and 14 (13.2%) required renal replacement therapy (RRT). After adjusting for LAS, RIFLE-F had an increased relative rate (RR) of in-hospital mortality (RR, 4.76, 95% confidence interval [CI], 1.65-13.7, p = 0.004) and 1-year mortality (RR, 3.17, 95% CI 1.55-6.49, p = 0.002). RIFLE-R and I were not associated with higher in-hospital or 1-year mortality. Post-operative RRT was associated with increased in-hospital (RR, 28.2; 95% CI, 6.18-128.1; p < 0.001) and 1-year mortality (RR, 4.97; 95% CI, 1.54-16.0; p < 0.001). AKI patients had higher median hospital charges of $168,146 vs $143,551 for no AKI (p = 0.02).

Conclusions: This study shows high rates of AKI using the new RIFLE criteria in LTx. RIFLE-F is associated with higher in-hospital and 1-year mortality. Less severe degrees of AKI are not associated with increased mortality. The financial burden associated with AKI is significant.