Additional file 1: Supplementary Figure 1. PLS-DA and RF analysis of serum metabolomic profiling at time zero. PLS-DA and RF analysis at time zero resulted in a good discrimination and prediction of the samples per BMI (A), but not per number of flares (B), or hyperuricemia (HU) > 8 mg/dL (C), or presence of tophi (D). Supplementary Figure 2. XOI-based ULT effects on serum metabolomic profiling. (A) PCA examining samples at time zero as well as at 12 and 24 weeks ULT titration to target. (B) Hierarchical clustering analysis at three time points. (C) Random Forest (RF) analysis using metabolite data derived from sera collected at baseline, or at 12 and 24 weeks ULT titration to target. (D) Top metabolites generated by RF analysis resulted in predictive accuracy of 52% (compared to 33% expected by random chance alone). Supplementary Figure 3. Validation of XOI-based ULT effects on xanthine and purine metabolism by serum metabolomic profiling. (A) Levels of ULT drugs included in the treatment and in metabolites related to purine and xanthine metabolism were significantly elevated in samples collected at 12- and 24-weeks treatment. Green: indicates significant difference (p≤0.05) between the groups shown, metabolite ratio of < 1.00. Light Green: narrowly missed statistical cutoff for significance 0.05