Ascertainment and epidemiology of acute kidney injury varies with definition interpretation.
OBJECTIVE
Differences in defining acute kidney injury (AKI) may impact incidence ascertainment. We assessed the effects of different AKI definition interpretation methods on epidemiology ascertainment.


METHODS
Two groups were studied at Texas Children's Hospital, Houston, Texas: 150 critically ill children (prospective) and 254 noncritically ill, hospitalized children receiving aminoglycosides (retrospective). SCr was collected for 14 d in the prospective study and 21 d in the retrospective study. Children with known baseline serum creatinine (bSCr) were classified by the pediatric Risk, Injury, Failure, Loss, End-Stage Kidney Disease (pRIFLE) AKI definition using SCr change (pRIFLE(DeltaSCr)), estimated creatinine clearance (eCCl) change (pRIFLE(DeltaCCl)), and the Acute Kidney Injury Network (AKIN) definition. In subjects without known bSCr, bSCR was estimated as eCCl = 100 (eCCl(100)) and 120 ml/min per 1.73 m(2) (eCCl(120)), admission SCr (AdmSCr) and lower/upper normative values (NormsMin, NormsMax). The differential impact of each AKI definition interpretation on incidence estimation and severity distribution was evaluated.


RESULTS
pRIFLE(DeltaSCr) and AKIN led to identical AKI distributions. pRIFLE(DeltaCCl) resulted in 14.5% (critically ill) and 11% (noncritical) more patients diagnosed with AKI compared to other methods (P 0.05). Different bSCr estimates led to differences in AKI incidence, from 12% (AdmSCr) to 87.8% (NormsMin) (P 0.05) in the critically ill group and from 4.6% (eCCl(100)) to 43.1% (NormsMin) (P 0.05) in the noncritical group.


CONCLUSIONS
AKI definition variation causes interstudy heterogeneity. AKI definition should be standardized so that results can be compared across studies.
Zappitelli
Michael
M
Montreal Children's Hospital, 2300 Tupper, Room E-222, Montreal, QC H3H1P3, Canada. mzaprdr@yahoo.ca
Parikh
Chirag R
CR
Akcan-Arikan
Ayse
A
Washburn
Kimberley K
KK
Moffett
Brady S
BS
Goldstein
Stuart L
SL
D000208:Acute Disease; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood*; D005260:Female; D006801:Humans; D015994:Incidence; D007674:Kidney Diseases / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology*; D007677:Kidney Function Tests / Q000592:standards*; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D009626:Terminology as Topic; D013781:Texas / Q000453:epidemiology; D013997:Time Factors
D015415:Biomarkers; D003404:Creatinine