Inflammatory patterns in rheumatoid arthritis estimated by the number of swollen and tender joints, the erythrocyte sedimentation rate, and hemoglobin: longterm course and association to radiographic progression

Abstract

Objective: To investigate the association of individual plots and time-integrated values of repeated measures of inflammatory variables with radiographic outcome in rheumatoid arthritis (RA).

Methods: In 112 patients with RA, examinations of joint swelling and joint tenderness of 68 joints, and measurement of hemoglobin (Hb) and erythrocyte sedimentation rate (ESR) were performed each year for up to 22 years after the first visit. For each of these 4 variables, the patients were divided arbitrarily into 5 characteristic subgroups by means of inspection of individual plots of longitudinal observations of the variables and divided into 5 other subgroups according to 20% percentiles of the cumulative mean values of the variables. The outcome of the subgroups was evaluated by varying degrees of radiographic events estimated by Larsen scoring of consecutive radiographs of 46 joints.

Results: An increasing number of radiographic events in subgroups with increasing severity (increasing values of joint swelling, joint tenderness, and ESR, decreasing values of Hb) was seen for both the arbitrary subgroups and the percentile subgroups of joint swelling, Hb, and ESR, whereas the association of joint tenderness to radiographic progression was weak.

Conclusion: A highly significant association between inflammatory variables and radiographic outcome could be observed, indicating that the degree of inflammation is important for the development of destructive joint damage in RA.