High uric acid, reduced glomerular filtration rate and non-alcoholic fatty liver in young people with obesity.

OBJECTIVE: To evaluate the association between high uric acid (UA), reduced estimated glomerular filtration rate (eGFR), and non-alcoholic fatty liver disease (NAFLD) in outpatient children and adolescents with overweight (OW) or obesity (OB). METHODS: Anthropometric, biochemical, hepatic ultrasound and eGFR data were available from 2565 young people with OW/OB (age 5-18 years). eGFR was calculated using the Schwartz's bedside formula and reduced eGFR (ReGFR+) was defined by a value < 90 mL/min/1.73 m2. High UA was defined as >= 75th percentile by sex in children and adolescents. RESULTS: The population was stratified in four categories: (1) normal eGFR and absence of NAFLD (ReGFR-/NAFLD-) (n = 1,236); (2) ReGFR+ and absence of NAFLD (ReGFR+/NAFLD- (n = 155); (3) normal eGFR and presence of NAFLD (ReGFR-/NAFLD+) (n = 1019); (4) presence of both conditions (ReGFR+/NAFLD+) (n = 155). Proportions of youth with high UA across the four categories were 17%, 30%, 33% and 46%, respectively (P < 0.0001). Young people with high levels of UA had odds ratio (95% CI) of 2.11 (1.43-3.11) for ReGFR+; 2.82 (2.26-3.45) for NAFLD+; and 5.04 (3.45-7.39) for both conditions (P < 0.0001 for all), independently of major confounders. CONCLUSIONS: High levels of UA were independently associated with ReGFR, NAFLD and the combination of both conditions in young people with OW/OB. The strength of this association was the highest in cases presenting both reduced eGFR and NAFLD. UA may serve as marker to identify patients at risk for these conditions.