We investigated the relationship between serum bilirubin and disease activity in patients with rheumatoid arthritis (RA).
We included a total of 173 consecutive RA patients without steroid treatment and 346 healthy subjects; the disease activity score in 28 joints (DAS28) was used to assess disease activity in patients with RA.
Serum bilirubin concentrations were significantly lower in RA patients than in controls. Serum bilirubin was found to be negatively correlated with C-reactive protein (CRP) concentration and erythrocyte sedimentation rate (ESR) (r=-0.165, P=0.030; r=-192, P=0.012) in patients with RA. There was a negative correlation between the serum bilirubin and DAS28 score (r=-0.331, P<0.001). Serum bilirubin was independently associated with the DAS28 score (b=-0.225, P=0.001) in the multiple linear regression analysis.
Serum bilirubin concentrations are lower in patients with RA compared to controls and correlate with disease activity in patients with RA.