Transient and Persistent AKI and Outcomes in Patients Undergoing Major Abdominal Surgery

Introduction: Acute kidney injury (AKI) is a frequent diagnosis in surgical patients which has a detrimental effect on short-term and long-term outcomes. The purpose of this study was to evaluate the incidence and predictive factors of transient and persistent postoperative AKI in patients submitted to major abdominal surgery and to characterize the impact of AKI on in-hospital mortality. Methods: This study was a cross-examination of a retrospective analysis of clinical data of 450 patients who underwent major abdominal surgery from January 2010 to February 2011. Only AKI developing in the first 48 h after surgery was considered. AKI was diagnosed using the Kidney Disease: Improving Global Outcome (KDIGO) classification based on both serum creatinine (SCr) and urine output criteria. Persistent and transient AKI were defined according to the Acute Disease Quality Initiative (ADQI) workgroup definitions. Results: In our study, 22.4% of patients developed AKI in the first 48 h post-surgery (n = 101), and 48% of patients had persistent AKI (n = 49), defined as postoperative AKI, with a duration of more than 48 h. Older age (adjusted odds ratio [OR] 1.06 [1.00–1.11], p = 0.039), hypertension (adjusted OR 4.60 [1.17–18.11], p = 0.029), and higher preoperative SCr (adjusted OR 22.67 [4.00–128.46], p < 0.001) were independent predictors of persistent AKI. The overall in-hospital mortality was 6.4% (n = 29). Persistent AKI was associated with higher mortality than transient AKI (51.9 vs. 20.7%; unadjusted OR 13.03 [5.78–29.36], p < 0.001; adjusted OR 4.20 [1.02–17.27], p = 0.047). Conclusion: In this cohort of patients submitted to major abdominal surgery, persistent AKI was an independent predictor of in-hospital mortality in contrast to transient AKI.