BackgroundCardiovascular disease (CVD) is the main cause of mortality in Rheumatoid Arthritis (RA). ObjectiveTo investigate the effect of biologic disease modifying anti-rheumatic drugs (bDMARDs) on lipids and CVD risk and evaluate associations with changes in systemic inflammation. MethodsPatients with RA initiating a bDMARD were evaluated at baseline, 3 and 6 months later. Longitudinal mixed effects models examined the association of individual biologics with changes in lipid levelsm Reynolds Risk Score (RRS) and Framingham risk score. Mediation by CRP, clinical disease activity index (CDAI) or swollen joint count on lipid changes were modeled using structural equation models. The correlation between CRP changes and LDL changes was estimated. Changes of LDL-C at 6 months among patients with low baseline LDL-C (<90 mg/dl) vs higher baseline LDL-C(90–130, and >130 mg/dl) were compared. The association between LDL-C changes across baseline LDL-C groups and disease activity improvement was evaluated. Results1698 bDMARD initiations were analyzed. Patients initiating tocilizumab had a significant increase in lipid levels but RRS at 3 and 6 months was similar across all biologics. Framingham risk score increased for patients treated with tocilizumab. Mediator analyses were statistically significant for the effects of CRP on lipid levels. Increases in LDL-C from baseline were independent of clinical response. An association of changes from baseline CRP and LDL-C were observed across all of the bDMARDs studied. ConclusionModerate increases in lipid levels on bDMARD treatment were not associated with an increased CVD risk by RRS regardless of the bDMARD initiated. Changes in CRP were significantly associated with changes in lipids in a mediator analysis.