Re-evaluating Renal Angina Index: An Authentic, Evidence-Based Instrument for Acute Kidney Injury Assessment: Critical Appraisal

Abstract

Background/Introduction: Renal angina index (RAI) used to calculate and accurately predict risk for the development of acute kidney injury (AKI) has been heavily explored. AKI is traditionally diagnosed by an increase in serum creatinine (SCr) concentration or oliguria, both of which are neither specific nor sensitive, especially among children. An RAI score may be calculated by combining objective signs of kidney dysfunction (such as SCr) and patient context, such as AKI risk factors, thus potentially serving as a more accurate indicator for AKI.Objective: Due to the propitious and novel nature of RAI, this editorial commentary aims to analyze the current literature on RAI and determine how well RAI serves as a predictor of AKI outcomes.Method: A comprehensive literature search was conducted in PubMed/Medline and Google Scholar between January 2012 and July 2020. Literature included the prognostic aspect of early prediction of AKI in the pediatric and adult population via RAI.Results: The initial literature search included 149 studies, and a total of 10 studies reporting the outcomes of interest were included. The overall sample size across these studies was 11,026. The predictive ability of RAI had a pooled (95% CI) sensitivity of 79.21%, specificity of 73.22%, and negative predictive value of 94.83%.Conclusion: RAI shows benefit in the prediction of AKI among adult and pediatric populations. However, there is a lack of sufficient data, and further prospective studies are needed in pediatric populations to use RAI as a principal AKI indicator among clinicians.

Evaluation of the Renal Angina Index to Predict the Development of Acute Kidney Injury in Children With Sepsis Who Live in Middle-Income Countries

“…Recognizing patients at risk of developing AKI through the RAI may lead to implementing early preventive measures and decrease complications secondary to AKI, with a possible impact on associated morbidity and mortality, hospital stay, and costs. [20][21][22] The RAI helps reliably differentiate children who will respond to conservative treatment from those who will need specialized renal treatment. 4 Studies have shown that an RAI ≥ 8 is useful for recognizing children with serious AKI who may require continuous renal support.…”

“…Furthermore, it seems that adding certain plasma biomarkers to the RAI may improve its discriminatory ability 20–23 . Basu et al 21 found that adding metalloproteinase 8 and neutrophil elastase 2 (ELA-2) measurement to the RAI increased its predictive ability from an AUC of 0.80 to an AUC of 0.88.…”

“…Furthermore, it seems that adding certain plasma biomarkers to the RAI may improve its discriminatory ability. [20][21][22][23] found that adding metalloproteinase 8 and elastase 2 (ELA-2) measurement to the RAI increased its predictive ability from an AUC of 0.80 to an AUC of 0.88. Unfortunately, these biomarkers are not widely available in all countries, they are costly, and validation is required in all care settings.…”

Predictive ability of renal angina index alone or in combination with biomarkers for detection of acute kidney injury in children

“…In addition, a higher RAI threshold (≥ 12 or ≥ 20) has been found to be more useful than RAI of ≥ 8 [19]. Recently, Raina et al [25] reported that predictive ability of RAI for AKI had a pooled sensitivity of 79.21%, specificity of 73.22% and negative predictive value of 94.83%, analyzed in 11,026 participants.…”

Evaluation of the Utility of the Renal Angina Index for the Early Diagnosis of Severe Acute Kidney Injury in Critically Ill Pediatric Patients in Three Institutions in Low-Resource Country

“…Early biomarkers based on the identi cation of structural injury have been proposed, but their application and availability at the patient's bedside in pediatric intensive care units present a series of validation and clinical context limitations [10][11][12][13][14][15]. In response to this need, the renal angina index (RAI) was introduced as an analogy to chest angina in acute myocardial infarction, serving as a tool for the early recognition of AKI in critically ill patients [16][17][18][19][20]. There is limited information regarding its use and applicability in pediatric intensive care units with moderate resources in Latin America.…”