Baseline and change in serum uric acid level over time and resolution of nonalcoholic fatty liver disease in young adults: The Kangbuk Samsung Health Study

Aims: To determine the association between: (i) baseline serum uric acid (SUA) level and (ii) SUA changes over time, and nonalcoholic fatty liver disease (NAFLD) resolution. Materials and Methods: A retrospective cohort study, comprising 38 483 subjects aged <40 years with pre-existing NAFLD, was undertaken. The effects of SUA changes over time were studied in 25 266 subjects. Participants underwent a health examination between 2011 and 2019, and at least one follow-up liver ultrasonography scan up to December 2020. Exposures included baseline SUA level and SUA changes between baseline and subsequent visits, categorized into quintiles. The reference group was the third quintile (Q3) containing zero change. The primary endpoint was resolution of NAFLD. Results: During a median follow-up of 4 years, low baseline SUA level and decreases in SUA levels over time were independently associated with NAFLD resolution (p for trend <0.001). Using SUA as a continuous variable, the likelihood of NAFLD resolution was increased by 10% and 13% in men and women, respectively, per 1-mg/dL decrease in SUA. In a time-dependent model with changes in SUA treated as a time-varying covariate, adjusted hazard ratios (95% confidence intervals) for NAFLD resolution comparing Q1 (highest decrease) and Q2 (slight decrease) to Q3 (reference) were 1.63 (1.49–1.78) and 1.23 (1.11–1.35) in men and 1.78 (1.49–2.12) and 1.18 (0.95–1.46) in women, respectively. Conclusions: Low baseline SUA levels and a decrease in SUA levels over time were both associated with NAFLD resolution in young adults.