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Fluid balance‐adjusted creatinine in diagnosing acute kidney injury in the critically ill
Author(s) -
Törnblom Sanna,
Wiersema Renske,
Prowle John R.,
Haapio Mikko,
Pettilä Ville,
Vaara Suvi T.
Publication year - 2021
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/aas.13841
Subject(s) - medicine , acute kidney injury , creatinine , confidence interval , incidence (geometry) , intensive care unit , kidney disease , renal replacement therapy , critically ill , renal function , mortality rate , post hoc analysis , intensive care medicine , optics , physics
Background Acute kidney injury (AKI) is often diagnosed based on plasma creatinine (Cr) only. Adjustment of Cr for cumulative fluid balance due to potential dilution of Cr and subsequently missed Cr‐based diagnosis of AKI has been suggested, albeit the physiological rationale for these adjustments is questionable. Furthermore, whether these adjustments lead to a different incidence of AKI when used in conjunction with urine output (UO) criteria is unknown. Methods This was a post hoc analysis of the Finnish Acute Kidney Injury study. Hourly UO and daily plasma Cr were measured during the first 5 days of intensive care unit admission. Cr values were adjusted following the previously used formula and combined with the UO criteria. Resulting incidences and mortality rates were compared with the results based on unadjusted values. Results In total, 2044 critically ill patients were analyzed. The mean difference between the adjusted and unadjusted Cr of all 7279 observations was 5 (±15) µmol/L. Using adjusted Cr in combination with UO and renal replacement therapy criteria resulted in the diagnosis of 19 (1%) additional AKI patients. The absolute difference in the incidence was 0.9% (95% confidence interval [CI]: 0.3%‐1.6%). Mortality rates were not significantly different between the reclassified AKI patients using the full set of Kidney Disease: Improving Global Outcomes criteria. Conclusion Fluid balance‐adjusted Cr resulted in little change in AKI incidence, and only minor differences in mortality between patients who changed category after adjustment and those who did not. Using adjusted Cr values to diagnose AKI does not seem worthwhile in critically ill patients.