Improvement in hepatic fibrosis estimated by Fibrosis-4 index in pegloticase treated chronic refractory gout patients

Objective To determine whether lowering serum urate (SU) affects the course of non-alcoholic fatty liver disease (NAFLD). Methods Retrospective data analysis from chronic refractory gout patients who participated in two 6-month pegloticase randomised clinical trials compared patients who received pegloticase biweekly to those who received placebo. Patients with persistent urate-lowering to <1 mg/dL in response to biweekly pegloticase (responders, n=36) were compared to those who received placebo (n=43). NAFLD was assessed using the Fibrosis-4 (Fib-4) index. Comparisons between groups were carried out using 2 sample Wilcoxon tests or regression analysis. Results At baseline the mean (standard deviation [SD]) Fib-4 values were 1.40 (0.86) in pegloticase responders, and 1.04 (0.53) in patients receiving placebo. Patients receiving placebo exhibited a change of 0.26 (0.41) in Fib-4 score over 6 months vs 0.13 (0.62) for pegloticase responders (p=0.048). When only patients with a Fib-4 value >1.3 were considered (n=27), a significant difference in the change in the Fib-4 values between pegloticase responders vs. placebo was observed (-0.15 [0.67] vs. 0.7 [0.42], p=0.04). The correlation between the SU area under the curve (AUC) over the 6-month trial period and the change in Fib-4 value was R=0.33 (p=0.0004). Multivariable analysis indicated SU AUC was the only significant contributor to the change in Fib-4 values (p=0.018). Conclusion Persistent lowering of SU significantly reduced Fib-4 scores, implying a possible effect on NAFLD progression. These results support the consideration of a complete analysis of the impact of profound urate-lowering on NAFLD as measured by the Fib-4 index.