Use of height-independent baseline creatinine imputation method with renal angina index

Area of Science:

• Pediatric Nephrology
• Critical Care Medicine
• Biostatistics

Background:

• The Renal Angina Index (RAI) predicts severe acute kidney injury (AKI) in pediatric intensive care units (PICUs).
• Accurate RAI calculation requires baseline serum creatinine (SCr), often unavailable in PICU settings.
• Current methods for estimating baseline SCr can be lacking or height-dependent.

Purpose of the Study:

• To evaluate an age-based, height-independent method for estimating baseline SCr for RAI calculation.
• To compare RAI scores derived from this new method against historical, height-based calculations.
• To assess the impact of the age-based method on RAI reclassification rates and AKI prediction.

Main Methods:

• An electronic algorithm calculated RAI scores using an age-based SCr imputation method (Pottel).
• 157 consecutive PICU patient records were reviewed, with 100 patients included for valid RAI calculation.
• RAI scores from the Pottel method were compared to historical RAI values, with reclassification rates as the primary outcome.

Main Results:

• Only two patients (2%) experienced RAI reclassification when using the Pottel age-based method compared to height imputation.
• The age-based method rarely led to significant overestimation or underestimation of baseline SCr.
• 15 out of 157 patients had a falsely positive RAI due to missing measured SCr or height data.

Conclusions:

• An age-based, height-independent method provides a practical alternative for baseline SCr estimation in RAI calculation.
• While less precise than height-based imputation, the age-based method demonstrates minimal impact on patient RAI status reclassification.
• This approach enhances the utility of RAI screening for AKI prediction in PICU settings where baseline SCr is often unavailable.