Comparison of diagnostic accuracy of screening tests ALT and ultrasound for pediatric non-alcoholic fatty liver disease

Laura G Draijer,Anneloes E Bohte,Jaap Stoker,Bart G P Koot,Sana Feddouli,Marc A Benninga,Olga Vd Baan Slootweg,Tammo H Pels Rijcken

doi:10.1007/s00431-019-03362-3

Abstract

Alanine aminotransferase (ALT) and ultrasound (US) are the most commonly used tools for detecting non-alcoholic fatty liver disease (NAFLD). No direct comparison of these two modalities in children exists. We aimed to compare head-to-head the diagnostic accuracy of ALT and US and their combination for detecting NAFLD in children with obesity. Ninety-nine children with severe obesity underwent simultaneous serum-ALT and abdominal ultrasound (US steatosis score 0–3). Proton magnetic resonance spectroscopy was used as reference standard for detecting steatosis/NAFLD. ROC curve analyses were performed to determine diagnostic performance and to determine optimum screening cut-points aiming for a specificity ≥ 80%. The area under the ROC (AUROC) of ALT and US were not significantly different (0.74 and 0.70, respectively). At the optimal ALT threshold (≥40 IU/L), sensitivity was 44% and specificity was 89%. At the optimal US steatosis score (≥ 2), sensitivity was 51% and specificity was 80%. Combining ALT and US did not result in better accuracy than ALT or US alone.Conclusion: ALT and US have comparable and only moderate diagnostic accuracy for detecting hepatic steatosis in children with obesity. A stepwise screening strategy combining both methods does not improve diagnostic accuracy.What is Known:• Alanine aminotransferase (ALT) and ultrasound (US) are the most commonly used tools for detecting non-alcoholic fatty liver disease (NAFLD).• ALT and ultrasound have mediocre accuracy in detecting steatosis in children with obesity.What is New:• In a head-to-head comparison, the difference in diagnostic accuracy of ALT and ultrasound in detecting steatosis is not significant.• A stepwise screening strategy combining both methods does not improve diagnostic accuracy.

Highlights

Non-alcoholic fatty liver disease (NAFLD) is well established as one of the complications of obesity
Comparing accuracy data from previous studies on the accuracy of these screening tests is difficult as study populations and reference standards differ among studies
The reported prevalence of non-alcoholic fatty liver disease (NAFLD) in children is 7.6% in general population studies and 38% in studies based on child obesity clinics [1,2,3]

Summary

Introduction

Non-alcoholic fatty liver disease (NAFLD) is well established as one of the complications of obesity. The reported prevalence of NAFLD in children is 7.6% in general population studies and 38% in studies based on child obesity clinics [1,2,3]. It is important to identify patients with obesity and NAFLD since advanced fibrosis is reported in up to 17% of children referred to liver centers after screening [4, 5]. In view of their long life expectancy, patients with significant fibrosis at pediatric age are at risk of long-term complications during their lifetime, i.e., cirrhosis, liver failure, and hepatocellular carcinoma. NAFLD is an independent risk factor for type 2 diabetes and, still disputed, probably for cardiovascular disease at adult age [6, 7]

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