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Prediction of acute kidney injury in intensive care unit patients

A Letter to this article was published on 19 February 2019

The Original Article was published on 18 August 2018

In their recent article assessing the predictive ability of urinary liver-type fatty-acid binding protein and serum N-terminal pro-B-type natriuretic peptide for acute kidney injury (AKI) in patients treated at a medical cardiac intensive care unit (ICU), Naruse et al. [1] did not provide any severity score, such as the APACHE II score or the SOFA score. The available evidence shows that patients’ severity of illness and level of organ failure upon admission to the ICU are independently associated with the occurrence of AKI [2, 3].

Furthermore, it was unclear whether the serum creatinine levels used for diagnosis of AKI had been corrected based on fluid balance. It has been shown that not adjusting serum creatinine levels for fluid balance can underestimate the incidence and severity of AKI in the ICU patients, as a positive fluid balance can dilute serum creatinine [4].

Finally, the discriminative ability of risk prediction models for AKI was assessed by c-statistic, but the calibration was not performed with the Hosmer-Lemeshow test. The calibration assesses the ability of a prediction model to match the number of actual events across deciles of risk-stratified subgroups. A P < 0.05 indicates poor calibration of the prediction model or a lack of fit between two models [5].



Acute kidney injury


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  5. Merkow RP, Hall BL, Cohen ME, Dimick JB, Wang E, Chow WB, et al. Relevance of the c-statistic when evaluating risk-adjustment models in surgery. J Am Coll Surg. 2012;214:822–30.

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RJG, FSX, and LJZS carefully read the manuscript by Naruse et al. and analyzed their methods and data. RJG suggested comment points and drafted this manuscript. FSX and LJZS revised the comment points and this manuscript. FSX is the author responsible for this manuscript. All authors read and approved the final manuscript.

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Correspondence to Fu-Shan Xue.

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Guo, RJ., Xue, FS. & Shao, LJZ. Prediction of acute kidney injury in intensive care unit patients. Crit Care 22, 304 (2018).

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