Prediction of acute kidney injury in cirrhotic patients: a new score combining renal, liver and inflammatory markers

Abstract

Introduction: Acute kidney injury (AKI) is common in hospitalized patients with cirrhosis and is associated with poor prognosis. A risk prediction score combining values easily measured at admission could be valuable to stratify patients for prevention, monitoring and early intervention, ultimately improving patient care and outcomes. The aim of this study was to develop a risk score for AKI in a cohort of cirrhotic patients.

Patients and methods: We cross-examined the data from a retrospective analysis of 186 patients with cirrhosis admitted to the Gastroenterology and Hepatology Service of Centro Hospitalar Lisboa Norte from January 2003 to December 2005. AKI was defined as an increase in serum creatinine (SCr)≥0.3 mg/dL within 48 hours or a percentage increase in SCr≥50% from baseline. Neutrophil-to-lymphocyte ratio (NLR) was used as a marker for inflammation. A receiver operating characteristic (ROC) curve was produced to assess the discriminative ability of the variables. Cutoff values were defined as those with highest validity. The final AKI risk score model was assessed using the ROC curve.

Results: A total of 52 patients (28%) developed AKI. Higher baseline SCr (p<0.001), more severe liver disease as evaluated by the modified Model of End-stage Liver Disease (MELD)-Na score (p<0.001) and higher NLR (p=0.028) were independently associated with AKI. The area under the ROC (AUROC) curve for the prediction of AKI was 0.791 (95% CI 0.726-0.847) for SCr, 0.771 (95% CI 0.704-0.829) for modified MELD-Na and 0.757 (95% CI 0.689-0.817) for NLR. Cutoff values with the highest validity for predicting AKI were determined and defined as 0.9 for the SCr, 21.7 for the modified MELD-Na and 6 for the NLR. The risk score was created allowing 3 points if the SCr is higher than 0.9, 1 point if the modified MELD-Na is higher than 21.7 and 1 point if the NLR is higher than 6. The AUROC curve of the risk prediction score for AKI was 0.861. A risk score of ≥2 points predicts AKI in cirrhotic patients with a sensitivity of 88.5% and specificity of 72.4%.

Conclusion: A new score combining SCr, MELD-Na and NLR demonstrated a strong discriminative ability to predict AKI in cirrhotic patients.

Keywords: acute kidney injury; cirrhosis; risk score.

Figure 1

AUC of the risk model for the prediction of AKI in cirrhotic patients. Abbreviations: AKI, acute kidney injury; AUC, area under the curve; ROC, receiver operating characteristic.