Recurrent kidney injury in critically ill surgical patients is common and associated with worse outcomes.
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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.


CONCLUSIONS
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.


METHODS
Prognostic and epidemiologic study, level III.
From the Division of General Surgery (D.G.H., G.K., M.P.M.), Department of Surgery, and R Adams Cowley Shock Trauma Center (T.M.S., W.C.C., J.J.D., M.E.L.), University of Maryland School of Medicine. Baltimore, Maryland.
Donald G
DG
Harris
Grace
G
Koo
Michelle P
MP
McCrone
Thomas M
TM
Scalea
William C
WC
Chiu
Jose J
JJ
Diaz
Matthew E
ME
Lissauer
D058186:Acute Kidney Injury / Q000175:diagnosis / Q000453:epidemiology*; D016638:Critical Illness; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D010351:Patient Discharge / Q000639:trends; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D015996:Survival Rate / Q000639:trends; D014481:United States / Q000453:epidemiology