Accuracy of prediction scores and novel biomarkers for predicting nonalcoholic fatty liver disease in obese children.

BACKGROUND: Accurate prediction scores for liver steatosis are demanded to enable clinicians to noninvasively screen for nonalcoholic fatty liver disease (NAFLD). Several prediction scores have been developed, however external validation is lacking. OBJECTIVE: The aim was to determine the diagnostic accuracy of four existing prediction scores in severely obese children, to develop a new prediction score using novel biomarkers and to compare these results to the performance of ultrasonography. DESIGN AND RESULTS: Liver steatosis was measured using proton magnetic resonance spectroscopy in 119 severely obese children (mean age 14.3 ± 2.1 years, BMI z-score 3.35 ± 0.35). Prevalence of steatosis was 47%. The four existing predictions scores ("NAFLD liver fat score," "fatty liver index," "hepatic steatosis index," and the pediatric prediction score) had only moderate diagnostic accuracy in this cohort (positive predictive value (PPV): 70, 61, 61, 69% and negative predictive value (NPV) 77, 69, 68, 75%, respectively). A new prediction score was built using anthropometry, routine biochemistry and novel biomarkers (leptin, adiponectin, TNF-alpha, IL-6, CK-18, FGF-21, and adiponutrin polymorphisms). The final model included ALT, HOMA, sex, and leptin. This equation (PPV 79% and NPV 80%) did not perform substantially better than the four other equations and did not outperform ultrasonography for excluding NAFLD (NPV 82%). CONCLUSION: The conclusion is in severely obese children and adolescents existing prediction scores and the tested novel biomarkers have insufficient diagnostic accuracy for diagnosing or excluding NAFLD.

Lifestyle intervention for non-alcoholic fatty liver disease: prospective cohort study of its efficacy and factors related to improvement.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) has a high prevalence in obese children. Lifestyle intervention is the primary treatment for NAFLD. However, limited data are available regarding the efficacy of lifestyle interventions. OBJECTIVES: To prospectively determine the efficacy of a lifestyle intervention programme on NAFLD in severely obese children and identify the clinical parameters related to improvement in NAFLD. METHODS: Children admitted to a lifestyle intervention programme were screened for NAFLD. Steatosis was defined as increased echogenicity of the liver on ultrasonography. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were used as surrogate markers for steatohepatitis. The lifestyle intervention programme consisted of physical exercise, dietary counselling and behavioural counselling for a period of 6 months. RESULTS: 144 children were included with a mean age of 14.1 (±2.3) years, BMI z-score of 3.35 (±0.40) kg/m(2). Lifestyle intervention significantly reduced the prevalence of steatosis (31.2-11.9%, p<0.001) and the prevalence of elevated serum ALT (25.7-11.1%, p<0.001) and serum AST (13.3-4.3%, p<0.002). In multivariate regression analysis, improvement in the degree of steatosis and decrease in ALT and AST were all significantly related to improvement in insulin resistance. Improvement in insulin resistance only explained a small part of the observed changes in transaminases. CONCLUSIONS: A lifestyle intervention of 6 months is moderately effective in improving NAFLD in severely obese children. Improvement in insulin resistance is the clinical parameter most strongly associated with improvement in NAFLD. Other factors related to the successful treatment of NAFLD need to be identified so that these can be a focus for new lifestyle and drug interventions.