Association between transient acute kidney injury and morbidity and mortality after lung transplantation: A retrospective cohort study

Purpose: Acute kidney injury (AKI) is a common occurrence after lung transplantation (LTx). Whether transient AKI or early recovery is associated with improved outcome is uncertain. Our aim was to describe the incidence, factors, and outcomes associated with transient AKI after LTx. Materials and Methods: We performed a retrospective cohort study of all adult recipients of LTx at the University of Alberta between 1990 and 2011. Our primary outcome transient AKI was defined as return of serum creatinine below Kidney Disease-Improving Global Outcome AKI stage I within 7 days after LTx. Secondary outcomes included occurrence of postoperative complications, mortality, and long-term kidney function. Results: Of 445 LTx patients enrolled, AKI occurred in 306 (68.8%) within the first week after LTx. Of these, transient AKI (or early recovery) occurred in 157 (51.3%). Transient AKI was associated with fewer complications including tracheostomy (17.2% vs 38.3%; P < .001), reintubation (16.4% vs 41.9%; P < .001), decreased duration of mechanical ventilation (median [interquartile range], 69 [41-142] vs 189 [63-403] hours; P < .001), and lower rates of chronic kidney disease at 3 months (28.5% vs 51.1%, P < .001) and 1 year (49.6% vs 66.7%, P = .01) compared with persistent AKI. Factors independently associated with persistent AKI were higher body mass index (per unit; odds ratio [OR], 0.91; 95% confidence interval, 0.85-0.98; P = .01), cyclosporine use (OR, 0.29; 0.12-0.67; P = .01), longer duration of mechanical ventilation (per hour [log transformed]; OR, 0.42; 0.21-0.81; P = .01), and AKI stages II to III (OR, 0.16; 0.08-0.29; P < .001). Persistent AKI was associated with higher adjusted hazard of death (hazard ratio, 1.77 [1.08-2.93]; P = .02) when compared with transient AKI (1.44 [0.93-2.19], P = .09) and no AKI (reference category), respectively. Conclusions: Transient AKI after LTx is associated with fewer complications and improved survival. Among survivors, persistent AKI portends an increased risk for long-term chronic kidney disease. (C) 2014 Elsevier Inc. All rights reserved.