Predictive models for kidney disease: improving global outcomes (KDIGO) defined acute kidney injury in UK cardiac surgery

Abstract

IntroductionAcute kidney injury (AKI) risk prediction scores are an objective and transparent means to enable cohort enrichment in clinical trials or to risk stratify patients preoperatively. Existing scores are limited in that they have been designed to predict only severe, or non-consensus AKI definitions and not less severe stages of AKI, which also have prognostic significance. The aim of this study was to develop and validate novel risk scores that could identify all patients at risk of AKI.MethodsProspective routinely collected clinical data (n = 30,854) were obtained from 3 UK cardiac surgical centres (Bristol, Birmingham and Wolverhampton). AKI was defined as per the Kidney Disease: Improving Global Outcomes (KDIGO) Guidelines. The model was developed using the Bristol and Birmingham datasets, and externally validated using the Wolverhampton data. Model discrimination was estimated using the area under the ROC curve (AUC). Model calibration was assessed using the Hosmer–Lemeshow test and calibration plots. Diagnostic utility was also compared to existing scores.ResultsThe risk prediction score for any stage AKI (AUC = 0.74 (95% confidence intervals (CI) 0.72, 0.76)) demonstrated better discrimination compared to the Euroscore and the Cleveland Clinic Score, and equivalent discrimination to the Mehta and Ng scores. The any stage AKI score demonstrated better calibration than the four comparison scores. A stage 3 AKI risk prediction score also demonstrated good discrimination (AUC = 0.78 (95% CI 0.75, 0.80)) as did the four comparison risk scores, but stage 3 AKI scores were less well calibrated.ConclusionsThis is the first risk score that accurately identifies patients at risk of any stage AKI. This score will be useful in the perioperative management of high risk patients as well as in clinical trial design.

High-Dose Perioperative Atorvastatin and Acute Kidney Injury Following Cardiac Surgery

“…2–4 Recent large cohort studies confirm that even mild postoperative AKI is independently associated with a five-fold increase in in-hospital death. 5 A diagnosis of AKI following cardiac surgery is accompanied by higher rates of postoperative arrhythmias, respiratory failure, systemic infection, and myocardial infarction. 1,5–7 Treatments are needed to reduce this debilitating postoperative outcome.…”

Management of post-operative acute kidney injury

“…This score did not include intra or post-operative variables allowing its application pre-operatively (14).…”

Acute Kidney Injury in the Surgical Patient

“…For patients undergoing non-cardiac surgery a few predictive models, developed in small cohorts utilizing limited intraoperative data or in larger cohorts but using only severe AKI as an end-point, are further limited by the lack of validation studies and provide only modest predictive accuracy [22, 112-114]. Recently UK AKI in Cardiac Surgery Collaborators group have developed and validated a new risk prediction score for any stage AKI after cardiac surgery with ROC-AUC of 0.74, providing better discrimination compared to previously published scores [115]. …”