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Abstract: TH-PO020

National AKI Risk Estimates After a Variety of Inpatient Surgeries

Session Information

Category: Acute Kidney Injury

  • 101 AKI: Epidemiology, Risk Factors, and Prevention


  • Saeed, Mohammed J., Capital Health, Trenton, New Jersey, United States
  • Alhamad, Tarek, Washington University in St. Louis, St. Louis, Missouri, United States

Postoperative acute kidney injury (AKI) is not well studied in non-cardiac procedures. Our aim was to quantify the risk of AKI and dialysis-requiring AKI (AKI-D) after various inpatient surgeries.


We used the National Inpatient Sample (NIS), which is a nationally representative sample of hospitalizations in the United States and includes records from all payers (including the uninsured). We identified 37 types of surgeries from 1/1/2013 to 9/30/2015 in adults (age ≥18 years) on first 2 days of hospitalization, excluding patients with end stage renal disease. Procedures, AKI and AKI-D were defined using ICD-9-CM diagnosis and procedure codes. Certain same-day surgery combinations were identified as well. Weighted frequencies and proportions of AKI and AKI-D were calculated for each surgery with 95% confidence intervals (CI).


Our study sample of 2,504,894 surgical hospitalizations represented 12,524,470 hospitalizations when weighted. AKI and AKI-D risk was plotted in figure 1 sorted by AKI risk. Surgeries with the highest AKI-D percentages were heart transplant (2.6%, 95% CI 1.0-4.2), liver transplant (3.7%, 95% CI 2.4-4.9) and abdominal aortic aneurysm repair (4.2%, 95% CI 3.4-5.0). Small bowel surgery had the highest AKI risk among bowel surgeries (8.7%, 95% CI 8.3-9.0) and had even higher risk when combined with colon surgery (18.3%, 95% CI 17.4-19.3) or with exploratory laparotomy (14.2%, 95% CI 13.5-14.8). Exploratory laparotomy combined with an abdominal procedure (except gastric and cesarean procedures) had significantly higher AKI risk (range of percentage difference 0.4-5.5).


Using nationally representative data, we estimated the risk of AKI and AKI-D in a large population of surgical hospitalizations including certain same-day surgery combinations.

Figure 1. AKI Risk After Inpatient Surgeries