TY - JOUR
T1 - A comparison of observed versus estimated baseline creatinine for determination of RIFLE class in patients with acute kidney injury
AU - Bagshaw, Sean M.
AU - Uchino, Shigehiko
AU - Cruz, Dinna
AU - Bellomo, Rinaldo
AU - Morimatsu, Hiroshi
AU - Morgera, Stanislao
AU - Schetz, Miet
AU - Tan, Ian
AU - Bouman, Catherine
AU - MacEdo, Etienne
AU - Gibney, Noel
AU - Tolwani, Ashita
AU - Oudemans-Van Straaten, Heleen M.
AU - Ronco, Claudio
AU - Kellum, John A.
N1 - Funding Information:
Acknowledgements. S.M.B was supported by a Clinical Investigator Award from the Alberta Heritage Foundation for Medical Research. This study was funded in part by an unrestricted educational grant from the Austin Hospital Intensive Care Trust Fund. This study was presented in poster format at the American Society of Nephrology Renal Week in Philadelphia, 6 November 2008 (abstract number 556022).
PY - 2009/9
Y1 - 2009/9
N2 - Background. The RIFLE classification scheme for acute kidney injury (AKI) is based on relative changes in serum creatinine (SCr) and on urine output. The SCr criteria, therefore, require a pre-morbid baseline value. When unknown, current recommendations are to estimate a baseline SCr by the MDRD equation. However, the MDRD approach assumes a glomerular filtration rate of ∼75 mLmin1.73 m2. This method has not been validated.Methods. Data from the Beginning and Ending Supportive Therapy for the Kidney (BEST Kidney) study, a prospective observational study from 54 ICUs in 23 countries of critically ill patients with severe AKI, were analysed. The RIFLE class was determined by using observed (o) pre-morbid and estimated (e) baseline SCr values. Agreement was evaluated by correlation coefficients and Bland-Altman plots. Sensitivity analysis by chronic kidney disease (CKD) status was performed.Results. Seventy-six percent of patients (n = 1327) had a pre-morbid baseline SCr, and 1314 had complete data for evaluation. Forty-six percent had CKD. The median (IQR) values were 97 μmolL (79-150) for oSCr and 88 μmolL (71-97) for eSCr. The oSCr and eSCr determined at ICU admission and at study enrolment showed only a modest correlation (r = 0.49, r = 0.39). At ICU admission and study enrolment, eSCr misclassified 18.8 and 11.7 of patients as having AKI compared with oSCr. Exclusion of CKD patients improved the correlation between oSCr and eSCr at ICU admission and study enrolment (r = 0.90, r = 0.84) resulting in 6.6 and 4.0 being misclassified, respectively.Conclusions. While limited, estimating baseline SCr by the MDRD equation when pre-morbid SCr is unavailable would appear to perform reasonably well for determining the RIFLE categories only if and when pre-morbid GFR was near normal. However, in patients with suspected CKD, the use of MDRD to estimate baseline SCr overestimates the incidence of AKI and should not likely be used. Improved methods to estimate baseline SCr are needed.
AB - Background. The RIFLE classification scheme for acute kidney injury (AKI) is based on relative changes in serum creatinine (SCr) and on urine output. The SCr criteria, therefore, require a pre-morbid baseline value. When unknown, current recommendations are to estimate a baseline SCr by the MDRD equation. However, the MDRD approach assumes a glomerular filtration rate of ∼75 mLmin1.73 m2. This method has not been validated.Methods. Data from the Beginning and Ending Supportive Therapy for the Kidney (BEST Kidney) study, a prospective observational study from 54 ICUs in 23 countries of critically ill patients with severe AKI, were analysed. The RIFLE class was determined by using observed (o) pre-morbid and estimated (e) baseline SCr values. Agreement was evaluated by correlation coefficients and Bland-Altman plots. Sensitivity analysis by chronic kidney disease (CKD) status was performed.Results. Seventy-six percent of patients (n = 1327) had a pre-morbid baseline SCr, and 1314 had complete data for evaluation. Forty-six percent had CKD. The median (IQR) values were 97 μmolL (79-150) for oSCr and 88 μmolL (71-97) for eSCr. The oSCr and eSCr determined at ICU admission and at study enrolment showed only a modest correlation (r = 0.49, r = 0.39). At ICU admission and study enrolment, eSCr misclassified 18.8 and 11.7 of patients as having AKI compared with oSCr. Exclusion of CKD patients improved the correlation between oSCr and eSCr at ICU admission and study enrolment (r = 0.90, r = 0.84) resulting in 6.6 and 4.0 being misclassified, respectively.Conclusions. While limited, estimating baseline SCr by the MDRD equation when pre-morbid SCr is unavailable would appear to perform reasonably well for determining the RIFLE categories only if and when pre-morbid GFR was near normal. However, in patients with suspected CKD, the use of MDRD to estimate baseline SCr overestimates the incidence of AKI and should not likely be used. Improved methods to estimate baseline SCr are needed.
KW - Acute kidney injury
KW - Consensus definition
KW - Creatinine
KW - RIFLE criteria
KW - Validation
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U2 - 10.1093/ndt/gfp159
DO - 10.1093/ndt/gfp159
M3 - Article
C2 - 19349297
AN - SCOPUS:69249102393
SN - 0931-0509
VL - 24
SP - 2739
EP - 2744
JO - Nephrology Dialysis Transplantation
JF - Nephrology Dialysis Transplantation
IS - 9
ER -