Similarly, while other disease activity measures showed trends for inverse association with PON1 activity in the abatacept study of biologic naïve patients, PDUS-7 scores and swollen joint count assessments were the RA disease activity measures most closely correlated with impaired paraoxonase activity (r = − 0.45 and − 0.50, respectively, p = 0.03); lower PDUS and lower numbers of swollen joints were associated with higher paraoxonase activity. This evidence concerns the gene PON1 and rheumatoid arthritis.