Rapid reversal of acute kidney injury and hospital outcomes: a retrospective cohort study.
BACKGROUND
Acute kidney injury (AKI), defined as an increment in serum creatinine level of 0.3 mg/dL or greater in 48 hours, is associated with poor outcomes. The prognosis associated with an increased creatinine level, either on admission or that develops in the hospital (ie, AKI), that rapidly returns to normal is not known.


METHODS
Retrospective cohort study.


METHODS
6,033 patients admitted to medical wards of a community teaching hospital between 2005 and 2007.


METHODS
AKI was defined as an increase in serum creatinine level of 0.3 mg/dL or greater within 48 hours. Increased serum creatinine level on admission was defined as serum creatinine greater than1.2 mg/dL on hospital admission in patients who did not subsequently meet criteria for AKI. Patients with a serum creatinine level of 1.2 mg/dL or less who had no increase of 0.3 mg/dL or greater within 48 hours during their hospital stay served as controls.


METHODS
Mortality, length of stay, intensive care unit transfer, and discharge destination were outcomes of interest.


RESULTS
Of 6,033 patients, 735 had AKI. Of these, 443 (60%) had serum creatinine levels that subsequently decreased by 0.3 mg/dL or greater within 48 hours and 197 returned to normal levels within 48 hours. Overall, patients with AKI had significantly greater mortality rates (14.8%) than patients without AKI with increased serum creatinine levels on admission (2.5%) and controls (1.3%; P < 0.001). Patients with AKI with a serum creatinine level that returned to normal within 48 hours had substantially greater mortality rates (14.2%) than those who initially presented with an increased serum creatinine level on admission and subsequent serum creatinine level decrease of 0.3 mg/dL or greater to normal within 48 hours (2.5%; P < 0.01).


CONCLUSIONS
Sample sizes of subgroups were small. Causes of AKI and increases in serum creatinine levels on admission were not assessed.


CONCLUSIONS
An increase in serum creatinine level of 0.3 mg/dL or greater during 48 hours of hospitalization predicts outcomes even if the value returns to normal. Patients who present to the hospital with an increased creatinine level that returns rapidly to normal have outcomes approaching those with serum creatinine levels consistently in the normal range.
Bridgeport Hospital and Yale University School of Medicine, Bridgeport, CT 06610, USA.
Jianmin
J
Tian
Fidel
F
Barrantes
Yaw
Y
Amoateng-Adjepong
Constantine A
CA
Manthous
D058186:Acute Kidney Injury / Q000097:blood / Q000453:epidemiology* / Q000628:therapy*; D000368:Aged; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data / Q000639:trends; D006785:Hospitals, University / Q000706:statistics & numerical data / Q000639:trends*; D006801:Humans; D007362:Intensive Care Units / Q000639:trends; D007902:Length of Stay / Q000639:trends; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
D003404:Creatinine