Supplemental digital content is available in the text.
Background: Acute kidney injury (AKI) is common in critically ill surgery patients. Patients who recover are at risk for recurrence, but recurrent kidney injury (RKI) is not well studied.
Methods: This was a retrospective 12-month cohort study of adults consecutively admitted to a noncardiac, non-trauma surgical intensive care unit. Patients were identified from a prospective critical care database, and kidney injury events were diagnosed and graded by RIFLE criteria. Patients who recovered from AKI were analyzed, and the primary end point was RKI (defined as kidney injury occurring after recovery from an index AKI event). Outcomes were inpatient and 1-year mortality, inpatient lengths of stay, and discharge creatinine.
Results: Of 624 patients, 296 (47%) had AKI and 216 (73%) recovered. Of these, 68 (31%) developed RKI. AKI in progress on hospital admission was associated with recurrence, but otherwise RKI and non-RKI patients had similar demographics, comorbidities, and inpatient clinical factors. Recurrence was associated with significantly higher inpatient and 12-month mortality, greater resource use, and worse discharge renal function.
Conclusion: RKI is common among critically ill surgical patients who recover from an index episode. Recurrence is a clinically significant event and is associated with worse renal and patient outcomes. Future studies should further define this process.
Level of evidence: Prognostic and epidemiologic study, level III.