Serum baseline hyaluronate and disease activity in rheumatoid arthritis.

The baseline serum hyaluronate (HA) concentration from samples obtained five to seven hours after mobilization of the patient was quantified using a radiometric 125I-HA binding method in 58 patients with rheumatoid arthritis and compared with several clinical and laboratory parameters by means of stepwise multiple linear regression. In the age- and sex-adjusted model, the variables with independent predictive value for serum hyaluronate concentration were the erythrocyte sedimentation rate (ESR) and the joint score index measuring the extent of the synovial inflammation. The estimated synovial mass index and C-reactive protein values did not improve the fit of the model after ESR and joint score were entered, and were left out from the multiple regression equation. When ESR and joint score were studied in univariate regression analysis with serum hyaluronate, the coefficients were r = 0.492 and r = 0.397, and the P values were P less than 0.001 and P less than 0.005, respectively. It was concluded that the baseline hyaluronate level in serum is closely related to the synovitic activity of the rheumatoid inflammation and that measurement of serum hyaluronate is of value when the activity and extent of synovial inflammation is being assessed in patients with rheumatoid arthritis.