Platzer A, Alasti F, Smolen JF, et al. - This study distinguishes and partly defines four different clusters of radiographic progression over time in patients with rheumatoid arthritis (RA), most remarkably one with relentless progression and another one with amelioration of joint damage over time, implying the existence of distinct patterns of joint damage accrual in RA.

• Researchers used 1,887 patients with 7,738 x-rays for cluster analyses.

• Four distinct clusters with characteristic shapes of radiographic progression were distinguished: one with a stable Sharp-van der Heijde scores (SHSs) over the whole 2-year period (C0/lowChange; 86%); one with relentless progression (C1/rise; 5.8%); one with decreasing SHS (C2/improvement; 6.9%); one going up and down (C3/bothWays; 1.4%) of the SHS.

• Using different clustering methods, the robustness of clusters was confirmed.

• It was shown that regression models distinguished disease duration, baseline C-reactive protein and SHS and treatment status as predictors for cluster assignment.