Article Text
Abstract
Objectives To determine the optimal threshold of blood and urine neutrophil gelatinase-associated lipocalin (NGAL) to predict moderate to severe acute kidney injury (AKI) and persistent moderate to severe AKI lasting at least 48 consecutive hours, as defined by an adjudication panel.
Methods A multicentre prospective observational study enrolled intensive care unit (ICU) patients and recorded daily ethylenediaminetetraacetic acid (EDTA) plasma, heparin plasma and urine NGAL. We used natural log-transformed NGAL in a logistic regression model to predict stage 2/3 AKI (defined by Kidney Disease International Global Organization). We performed the same analysis using the NGAL value at the start of persistent stage 2/3 AKI.
Results Of 245 subjects, 33 (13.5%) developed stage 2/3 AKI and 25 (10.2%) developed persistent stage 2/3 AKI. Predicting stage 2/3 AKI revealed the optimal NGAL cutoffs in EDTA plasma (142.0 ng/mL), heparin plasma (148.3 ng/mL) and urine (78.0 ng/mL) and yielded the following decision statistics: sensitivity (SN)=78.8%, specificity (SP)=73.0%, positive predictive value (PPV)=31.3%, negative predictive value (NPV)=95.7%, diagnostic accuracy (DA)=73.8% (EDTA plasma); SN=72.7%, SP=73.8%, PPV=30.4%, NPV=94.5%, DA=73.7% (heparin plasma); SN=69.7%, SP=76.8%, PPV=32.9%, NPV=94%, DA=75.8% (urine). The optimal NGAL cutoffs to predict persistent stage 2/3 AKI were similar: 148.3 ng/mL (EDTA plasma), 169.6 ng/mL (heparin plasma) and 79.0 ng/mL (urine) yielding: SN=84.0%, SP=73.5%, PPV=26.6%, NPV=97.6, DA=74.6% (EDTA plasma), SN=84%, SP=76.1%, PPV=26.8%, NPV=96.5%, DA=76.1% (heparin plasma) and SN=75%, SP=75.8%, PPV=26.1, NPV=96.4%, DA=75.7% (urine).
Conclusion Blood and urine NGAL predicted stage 2/3 AKI, as well as persistent 2/3 AKI in the ICU with acceptable decision statistics using a single cut point in each type of specimen.
- neutrophil gelatinase associated lipocalin
- acute kidney injury
- risk prediction
- sensitivity
- specificity
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Footnotes
Contributors PAM conceived the study. PME funded the study. AOG, MG, LG and LWM initiated the study design and helped with implementation. KMT conducted the statistical analysis. KMT and PAM drafted the article. All authors contributed to the manuscript's refinement and approved the final version.
Funding The study was funded by BioPorto Diagnostics A/S.
Competing interests EE, PME, and ML are employees of BioPorto Diagnostics A/S. The remaining authors have nothing to disclose.
Patient consent Obtained.
Ethics approval Institutional Review Board (Baystate Health IRB #1; Houston Methodist Research Institute (HMRI) IRB 1; Pratners Human Research Committee; Biomedical Research Alliance of New York (BRANY) IRB).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The data from this study will not be made available.