title: Incidence of nonconfounded post-computed tomography acute kidney injury in hospitalized patients with stable renal function receiving intravenous iodinated contrast material.
abstract: OBJECTIVE
  The purpose of our investigation was to determine the frequency of proximate acute and chronic confounding risk factors for acute kidney injury (AKI) in a cohort of adult hospitalized patients with stable renal function who developed AKI following an intravenous (IV) contrast-enhanced computed tomography (CT) examination.
  
  
  METHODS
  Institutional review board approval was obtained for this retrospective, Health Insurance Portability and Accountability Act-compliant investigation. Overall, 100 adult inpatients (50 males [mean age = 61 years, range: 24-94 years] and 50 females [mean age = 60 years, range: 20-95 years]) with stable pre-CT renal function who developed post-CT AKI using the Acute Kidney Injury Network (AKIN) laboratory criteria following an IV contrast-enhanced CT examination comprised the study population. Electronic International Classification of Disease-9 analysis followed by a comprehensive manual electronic medical record review was systematically performed by 5 radiologists to identify known acute (n = 24, within 5 days before or 3 days after CT) and chronic (n = 21) risk factors for AKI other than contrast material administration that might confound a diagnosis of contrast-induced nephrotoxicity. Descriptive statistics were performed.
  
  
  RESULTS
  Of 100 inpatients with post-CT AKI, 99 (99%) had 1 or more acute risk factor(s) for AKI other than contrast material administration (median = 3 risk factors, range: 0-8) and 86 (86%) had one or more chronic risk factor(s) for AKI (median = 2 risk factors, range: 0-7). The median number of risk factors (acute or chronic) per patient was 5 (range: 1-13). Only 1 inpatient (1%) developed post-CT AKI without a confounding acute risk factor (estimated glomerular filtration rate = 62-71 mL/min/1.73 m(2), 4 chronic risk factors, and CT 7 days after pancreaticoduodenectomy). The most common acute risk factors were nephrotoxic medications (83%) and parenteral blood product administration (30%). The most common chronic risk factors were hypertension (59%) and chronic kidney disease (56%).
  
  
  CONCLUSIONS
  Nonconfounded post-CT AKI is rare in hospitalized adults with stable renal function who have been exposed to IV low- or iso-osmolality iodinated contrast material.
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, MI.
authors.forename: Andreea
authors.initials: A
authors.lastname: Moore
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, MI.
authors.forename: Elliot
authors.initials: E
authors.lastname: Dickerson
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, MI.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Dillman
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, MI.
authors.forename: Dharshan
authors.initials: D
authors.lastname: Vummidi
authors.affiliation: Division of Pediatric Nephrology, Department of Pediatrics and Infectious Disease, University of Michigan Health System, Ann Arbor, MI.
authors.forename: David B
authors.initials: DB
authors.lastname: Kershaw
authors.affiliation: Michigan Institute for Clinical and Health Research, Ann Arbor, MI.
authors.forename: Shokoufeh
authors.initials: S
authors.lastname: Khalatbari
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, MI. Electronic address: matdaven@med.umich.edu.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Davenport
mesh_terms: D058186:Acute Kidney Injury / Q000139:chemically induced* / Q000453:epidemiology / Q000517:prevention & control; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000009:adverse effects*; D064420:Drug-Related Side Effects and Adverse Reactions; D005260:Female; D005919:Glomerular Filtration Rate; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D007275:Injections, Intravenous / Q000706:statistics & numerical data*; D007455:Iodine / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000009:adverse effects
chemical_list: D003287:Contrast Media; D007455:Iodine