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.