Fig. 3

Correlation of synovial markers with serum metabolites. a Linear regression was performed between each synovial marker–serum metabolite pair, controlling for age and gender. The regression coefficients for each pair were used to form a clustered heatmap, to lend insight into which groups of synovial markers were correlated with which groups of metabolites. The color bar along the top is preserved from Fig. 1, and indicates groups of similar cytokines. Row clusters have been identified by cophenetic cutting of the row dendrogram. b Metabolite regression p values are displayed in Fig. 3b, where the row and column order are preserved from Fig. 3a. APRIL, a proliferation-inducing ligand; BLyS, lymphocyte stimulator; MMP, matrix metalloproteinase; SDF1, S cell-derived factor 1