Development and External Validation a Novel Inflammation-Based Score for Acute Kidney Injury and Prognosis in Intensive Care Unit Patients

Abstract

Purpose We aimed to evaluate the predictive ability of an integrated score based on several inflammatory indices of acute kidney injury (AKI) in patients in the intensive care unit (ICU). Patients and Methods In this observational study, 2555 patients from the Medical Information Mart for Intensive Care III database were randomly assigned to the test set (n=1599) and internal validation set (n=656). Moreover, 412 coronary care unit patients from Zhongnan Hospital, Wuhan University were also included in the external validation set. The AKI-specific inflammatory index (ASII) was created using various inflammatory indices significantly associated with AKI. We further developed and validated two nomograms based on the ASII and other informative clinical features of AKI and prognosis. Results The ASII was calculated as 2.317×MLR+0.417×GPS+0.007×ALRI. In the training set, patients with a high ASII had a higher risk of incident AKI (odds ratio [OR], 5.33; 95% confidence index [CI], 3.60–7.88; P<0.001) than those with a low ASII with or without pre-existing chronic kidney disease. The nomograms for AKI and prognosis based on the ASII and other significant clinical characteristics had high predictive value in the prediction of AKI and prognosis in patients in the ICU. Moreover, the results in the internal validation set and in the external validation cohort were almost consistent with those in the training set. Conclusion The ASII is an AKI-specific tool based on the combination of available inflammatory indices. A high ASII is a strong predictor of a higher risk of AKI and worse survival outcomes in patients in the ICU.