To describe the course of radiological progression in a cohort of 126 patients presenting with early nonerosive rheumatoid arthritis (RA).
Criteria for recruitment to the study were fulfillment of the 1958 American Rheumatism Association criteria, absence of erosive disease at presentation and duration of symptoms less than 3 years. Radiographs of hands and feet at 0, 1, 2, 5, and 8 years were available on 114 patients and were scored by Sharp's method for erosion (ERO) and joint space narrowing (JSN). Eighty-six patients were typed for the RA susceptibility shared HLA-DR epitope.
The feet showed greatest initial radiological progression, but tended to reach an earlier and lower plateau. ERO progressed more rapidly than JSN in the first 2 years, but in parallel thereafter. The relative proportion of ERO:JSN varied, 1:1 for the wrists, 4:1 for the proximal interphalangeal joints. Thirty-eight percent of joints were eroded at 2 years, 63% at 8 years. Four patterns of radiological progression were identified: flat or nonerosive disease in 29 patients, linear in 51, lag in 13, and plateau in 19 (irregular in 2). Changes in the rate of radiological progression were reflected by the time-integrated C-reactive protein over the same period. Rheumatoid factor titer was higher in the progressive groups compared to the flat group (p = 0.01). The RA susceptibility shared HLA-DR epitope was more frequent in the linear compared to the flat group (p = 0.03).
A large proportion of joints become eroded in the first 2 years of early RA. The subsequent course of radiological progression is highly variable and cannot be easily explained by any single model.