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Kidney Week

Abstract: TH-PO015

Improvement of the Renal Angina Index Clinical Application Through Multiple Baseline Creatinine estimation Methods

Session Information

Category: Acute Kidney Injury

  • 101 AKI: Epidemiology, Risk Factors, and Prevention

Authors

  • Roy, Jean-Philippe, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Goldstein, Stuart, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
Background

The Renal Angina Index (RAI) is a validated screening tool used at 12h of pediatric intensive care unit (PICU) admission that predicts severe AKI on PICU day 3. A baseline serum creatinine (SCr) value is essential for AKI diagnosis as well as RAI, yet, is often not available. In this situation, our RAI algorithm uses a validated height-dependent imputation method (Baseline SCr (mg/dL) = 0.413 x height (cm) / 120ml/min/1.73m2), yet patient height often is not available in the medical record within 12 hours of PICU admission. To improve the reliability of the RAI algorithm, we compared the height-dependent method with an age-based, height-independent baseline SCr calculation.

Methods

In April 2017, we implemented an electronic algorithm to automatically generate an RAI score for every patient (pt) admitted to our PICU. We reviewed 157 pt records from May 2017, selecting those who had an appropriate calculation of their RAI at 12h. We compared the RAI using an age-based SCr imputation method of Pottel to the RAI using a SCr imputed by the height-dependent method. Our primary outcome was a change in fulfillment of the RAI positivity threshold (RAI>8). A secondary outcome compared height-based imputed and age-based baseline SCr to assess for a discrepancy of >25% between the two methods.

Results

We found 15/157 false positive RAI results on screening due to a lack of previously measured SCr and height, 42 without SCr measurement within 12h of their admission, leaving 100 that had sufficient data for RAI calculation. Only 2/100 pt had the RAI reclassified when using the Pottel imputed baseline SCr (one in each direction). 20% of pt had a discrepancy of 25% or more between the two methods. A Cochrane-Mantel-Haenszel Chi-square test confirmed that being small for age (<3rd percentile of height) or being older (≥14 years old) were both independently associated with an overestimation of the baseline SCr when using the age-based method.

Conclusion

The age-based method to estimate baseline SCr offers a viable height-independent alternative for RAI calculation. While being less precise than a height-based approach, this lack of precision rarely leads to reclassification of pt RAI status.