Patterns of radiographic outcomes in early, seropositive rheumatoid arthritis: A baseline analysis

We examine radiographic profile patterns using clustering algorithms to assess progression rates at set time intervals in a rheumatoid arthritis (RA) observational study. Hands/feet radiographic scores were analyzed for 190 early, seropositive RA patients with ≥3 radiographic observations from a prospective cohort. Assessments at 6months, 1year, and yearly thereafter were requested for demographic, therapeutic, functional, laboratory, radiographic, and clinical data. Progression rates for the total sharp scores [erosion (E)+joint space narrowing (JSN)] were interpolated for intervals of 0 to 6months, 6month–1year, 1–2years, and 2–3years past first radiographic observation. Patients were grouped on their sets of rates by K-median clustering algorithms, and categorical group membership was regressed onto baseline characteristics using multinomial models. The number of clusters was determined using one-way MANOVA, and baseline differences across clusters by Kruskal–Wallis tests.