Abstract
Although there is clear face validity that structural damage is related to outcome, it is difficult to prove this. Recently, more evidence became available that structural damage, as assessed on plain films, is indeed related to disease activity in clinical trials and therefore can be used to assess the effect of treatment. Also, a relationship between structural damage and outcome, mainly defined as physical disability, was established. Several examples of findings in recent publications are presented which lead to the following conclusions. There is a relation between the response to treatment measured as clinical disease activity and measured as radiographic progression in most clinical therapeutic trials. A strong relation between local inflammation and progression of damage in the individual joint is present. This is robust evidence for the hypothesis that inflammation leads to structural damage. There is a good relation between the damage in small and large joints as assessed on plain films. Damage measured in small joints is a good substitute for overall damage. Disease activity is always strongly correlated with functional disability throughout the disease course. There is an increasing relation between disability and structural damage with increasing disease duration.