Long-Term Risk of Mortality and Acute Kidney Injury During... : Annals of Surgery (original) (raw)

Original Articles

Long-Term Risk of Mortality and Acute Kidney Injury During Hospitalization After Major Surgery

Bihorac, Azra MD*; Yavas, Sinan MD*; Subbiah, Sophie BA*; Hobson, Charles E. MD†; Schold, Jesse D. PhD‡; Gabrielli, Andrea MD*; Layon, A Joseph MD*; Segal, Mark S. MD, PhD‡

From the *Division of Critical Care Medicine, Department of Anesthesiology, †Department of Surgery, and ‡Division of Nephrology, Hypertension and Transplantation, Department of Medicine, University of Florida College of Medicine, Gainesville, Florida.

Supported by the Department of Anesthesiology and Gatorade Research funds, University of Florida College of Medicine.

The funding organizations did not have any role in the design and conduct of the study, in the collection, management, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.

Reprints: Azra Bihorac, MD, FASN, Department of Anesthesiology, University of Florida College of Medicine, 1600 SW Archer Rd., PO Box 100254, Gainesville, FL 32610-0254. E-mail: [email protected].

Objective:

To determine the relationship between long-term mortality and acute kidney injury (AKI) during hospitalization after major surgery.

Summary Background Data:

AKI is associated with a risk of short-term mortality that is proportional to its severity; however the long-term survival of patients with AKI is poorly studied.

Methods:

This is a retrospective cohort study of 10,518 patients with no history of chronic kidney disease who were discharged after a major surgery between 1992 and 2002. AKI was defined by the RIFLE (Risk, Injury, Failure, Loss, and End-stage Kidney) classification, which requires at least a 50% increase in serum creatinine (sCr) and stratifies patients into 3 severity stages: risk, injury, and failure. Patient survival was determined through the National Social Security Death Index. Long-term survival was analyzed using a risk-adjusted Cox proportional hazards regression model.

Results:

In the risk-adjusted model, survival was worse among patients with AKI and was proportional to its severity with an adjusted hazard ratio of 1.18 (95% confidence interval [CI], 1.08–1.29) for the RIFLE-Risk class and 1.57 (95% CI, 1.40–1.75) for the RIFLE-Failure class, compared with patients without AKI (P < 0.001). Patients with complete renal recovery after AKI still had an increased adjusted hazard ratio for death of 1.20 (95% CI, 1.10–1.31) compared with patients without AKI (P < 0.001).

Conclusions:

In a large single-center cohort of patients discharged after major surgery, AKI with even small changes in sCr level during hospitalization was associated with an independent long-term risk of death.