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

Abstract

Background The Renal Angina Index (RAI) is a validated screening tool used at 12 h of pediatric intensive care unit (PICU) admission to predict severe acute kidney injury (AKI) on day 3 of PICU stay. A measured or height-imputed baseline serum creatinine (SCr) is required for AKI diagnosis and RAI calculation, yet these are often lacking. We assessed an age-based, height-independent baseline SCr calculation and compared the RAI values employing this method to their historical counterpart. Methods An electronic algorithm was implemented to generate RAI score for patients admitted to our PICU. We reviewed 157 consecutive patient records from May 2017, until we cumulated 100 with a valid RAI calculation. We compared RAI scores using the age-based SCr imputation method of Pottel to the historical RAI. Our primary outcome was a difference in the rate of RAI fulfillment (≥8) reclassification between methods. Results Of the first 100 patients, 27 had measured baseline SCr and 73 used height imputation. Only two patients had RAI reclassified with the Pottel method (one in each direction). Being small for age or older were associated with ≥25% overestimation of the baseline SCr in 20 patients with the Pottel method compared with height imputation. 15/157 patients had a falsely positive RAI due to lack of measured baseline SCr and height. Conclusion The age-based method to estimate baseline SCr offers a viable height-independent alternative for RAI calculation. While less precise than a height-based approach, this lack of precision rarely leads to reclassification of patient RAI status.

Identifying critically ill children at high risk of acute kidney injury and renal replacement therapy

“…Calculation of baseline creatinine values using the Schwartz equation has been previously validated and widely used [ 2 ], but relies on height measurements which we did not have. We therefore conducted a secondary analysis using the Pottel method [ 15 ] to impute baseline creatinine values for those with absent data, following the method of Roy et al [ 16 ].…”

Integration of the Renal Angina Index and Urine Neutrophil Gelatinase-Associated Lipocalin Improves Severe Acute Kidney Injury Prediction in Critically Ill Children and Young Adults

“…The most common reasons for unavailability of an NGAL result were as follows: RAI incorrectly calculated as <8 resulting in error (79.3%), NGAL order not included in admission order set (8.6%), and not enough urine produced to send for NGAL test (5.2%). The RAI calculation error occurred for patients with recent transplant that had not been entered into the patient diagnosis list or inability to calculate estimated creatinine clearance because of missing patient height (which was corrected early in the study course 16 ). The distribution of NGAL concentrations was <150 ng/ml ( n = 39), 150–499 mg/ml ( n = 19), and >500 ng/ml ( n = 34).…”

“…We reported the successful development and validation of a real-time RAI notification system at our center. 16 Although the calculation of the RAI is simple, computation-based patient stratification systems such as the RAI must be reliable and reported in real time for clinician acceptance into the CDS. Traditional patient scoring systems rely on busy clinicians or research coordinators removed from the bedside for manual data extraction and tabulation.…”

“…If no height is available, it uses patient age to impute a baseline SCr with a similar accuracy, as we have previously validated in the early stages of this project. 16 If the RAI result is <8, the patient receives the routine clinical standard of care, and no further action is directed by the CDS pathway.…”

Risk Factors for Sepsis-Associated Acute Kidney Injury in the PICU: A Retrospective Cohort Study

“…Baseline serum creatinine was defined as the lowest serum creatinine measured within the 3 months prior to admission (14). If no serum creatinine was measured in this period, the baseline serum creatinine was estimated using previously validated methods (14)(15)(16)(17). The Kidney Disease Improving Global Outcomes (KDIGO) serum creatinine and urine output criteria (18) were used to define and stage AKI.…”