Abstract
This study aimed to examine the progression of large joint involvement from early to established RA in terms of range of movement (ROM) and time to joint surgery, according to the presence of rheumatoid factor (RF). We used a historical longitudinal cohort of early RA patients. Patients were deemed RF negative if all repeated assessments were negative. The rate of progression from normal to any loss of range of movement (ROM) from years 3 to 14 were modelled using generalized estimating equations, for elbows, wrists, hips, knees and ankle, adjusting for confounders. Time to joint surgery was analysed using multivariable Cox models. A total of 1458 patients were included (66% female, mean age 55 years) and 74% were RF-positive. The prevalence of any loss of ROM, from year 3 through to 14 was highest in the wrist followed by ankle, knee, elbow and hip. Odds of loss of ROM increased over time in all joint regions assessed, at around 7-13% per year from year 3 to 14. Time to surgery was similar according to RF-status for the wrist and ankle, but RF-positive cases had a lower hazard of surgery at the elbow (HR 0.37, 0.15-0.90), hip (HR 0.69, 0.48-0.99) and after 10 years at the knee (HR 0.41, 0.25-0.68). Large joints become progressively involved in RA, most frequently affecting the wrist followed by ankle, which is overlooked in composite disease activity indices. RF-negative and positive cases progressed similarly. Treat-to-target approaches should be followed irrespective of RF status.