Fig. 1

A multi-approach discovery strategy to identify metabolites indicative of RA disease activity. (A) Differentially abundant metabolites between the higher and lower disease activity groups were identified using a mixed-effects logistic regression model adjusted for patient age and sex, as well as for patient ID to control for having multiple samples from the same patient. (B) A selection scheme to identify metabolites associated with DAS28-CRP. Metabolites were selected with mixed-effects linear regression. To further demonstrate their association with DAS28-CRP, these metabolites were used to construct a generalized linear model for predicting DAS28-CRP. The predictive performance of the model was evaluated on the discovery cohort (using a cross-validation technique) and on a validation cohort