Acute Kidney Injury After Major Surgery: A Retrospective Analysis of Veterans Health Administration Data.
BACKGROUND
Few trials of acute kidney injury (AKI) prevention after surgery have been conducted, and most observational studies focus on AKI following cardiac surgery. The frequency of, risk factors for, and outcomes after AKI following other types of major surgery have not been well characterized and may present additional opportunities for trials in AKI.


METHODS
Observational cohort study.


METHODS
3.6 million US veterans followed up from 2004 to 2011 for the receipt of major surgery (cardiac; general; ear, nose, and throat; thoracic; vascular; urologic; and orthopedic) and postoperative outcomes.


METHODS
Demographics, health characteristics, and type of surgery.


RESULTS
Postoperative AKI defined by the KDIGO creatinine criteria, postoperative length of stay, end-stage renal disease, and mortality.


RESULTS
Postoperative AKI occurred in 11.8% of the 161,185 major surgery hospitalizations (stage 1, 76%; stage 2, 15%, stage 3 [without dialysis], 7%; and AKI requiring dialysis, 2%). Cardiac surgery had the highest postoperative AKI risk (relative risk [RR], 1.22; 95% CI, 1.17-1.27), followed by general (reference), thoracic (RR, 0.92; 95% CI, 0.87-0.98), orthopedic (RR, 0.70; 95% CI, 0.67-0.73), vascular (RR, 0.68; 95% CI, 0.64-0.71), urologic (RR, 0.65; 95% CI, 0.61-0.69), and ear, nose, and throat (RR, 0.32; 95% CI, 0.28-0.37) surgery. Risk factors for postoperative AKI included older age, African American race, hypertension, diabetes mellitus, and, for estimated glomerular filtration rate < 90mL/min/1.73m(2), lower estimated glomerular filtration rate. Participants with postoperative AKI had longer lengths of stay (15.8 vs 8.6 days) and higher rates of 30-day hospital readmission (21% vs 13%), 1-year end-stage renal disease (0.94% vs 0.05%), and mortality (19% vs 8%), with similar associations by type of surgery and more severe stage of AKI relating to poorer outcomes.


CONCLUSIONS
Urine output was not available to classify AKI; cohort included mostly men.


CONCLUSIONS
AKI was common after major surgery, with similar risk factor and outcome associations across surgery type. These results can inform the design of clinical trials in postoperative AKI to the noncardiac surgery setting.
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD. Electronic address: mgrams2@jhmi.edu.
Morgan E
ME
Grams
Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD.
Yingying
Y
Sang
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD; Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD.
Josef
J
Coresh
Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD.
Shoshana
S
Ballew
Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD.
Kunihiro
K
Matsushita
Division of Nephrology, University of Tennessee Health Science Center, Memphis, TN.
Miklos Z
MZ
Molnar
Department of Cardiothoracic Surgery and Cardiothoracic Anesthesia, Linköping University Hospital, Linköping, Sweden; Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
Zoltan
Z
Szabo
Harold Simmons Center for Chronic Disease Research & Epidemiology, University of California Irvine Medical Center, Irvine, CA; Division of Nephrology & Hypertension, University of California Irvine Medical Center, Orange, CA.
Kamyar
K
Kalantar-Zadeh
Division of Nephrology, University of Tennessee Health Science Center, Memphis, TN; Nephrology Section, Memphis Veterans Affairs Medical Center, Memphis, TN.
Csaba P
CP
Kovesdy
D058186:Acute Kidney Injury / Q000453:epidemiology*; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D058014:Veterans Health
Acute kidney injury (AKI); KDIGO creatinine criteria; end-stage renal disease (ESRD); hospital length of stay; kidney function; mortality; postoperative AKI; surgery; surgical complication