The correlation of serum bilirubin levels with disease activity in patients with rheumatoid arthritis.

BACKGROUND: We investigated the relationship between serum bilirubin and disease activity in patients with rheumatoid arthritis (RA).

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: Serum bilirubin concentrations are lower in patients with RA compared to controls and correlate with disease activity in patients with RA.