Rheumatoid arthritis disease measurement: a new old idea

In many medical treatment areas, the use of treatment targets has led to improved outcomes, including a reduction in end-organ damage. In rheumatology, appropriate targets appear elusive, although preventing joint damage, minimizing disability and improving mortality are end results on which most clinicians would agree. Sophisticated measures of disease activity, particularly in early disease, have only recently been objectively evaluated. Swollen joint count, tender joint count, acute-phase reactants, citrullinated antibody titres (ACPAs), patient and physician assessment of disease activity, radiographs and other imaging modalities such as US and MRI may all be appropriate to measure. A number of composite measures have been proposed as possible or practical methods for defining RA disease activity. Some require testing of acute-phase reactants, but several do not. ACR20/50/70 scores are useful for measuring change from visit to visit, while others (DAS28, HAQ, Simplified Disease Activity Index, Clinical Disease Activity Index and Routine Assessment of Patient Index Data) assess disease activity at a single point. Disease measures have now been used in myriad clinical trials and studies. The FIN-RACo, TICORA, CAMERA and BeSt trials employed measures of disease activity at predetermined points to guide treatment decisions. These trials supported the consistent use of objective measures to derive significant benefits from treat-to-target strategies. The concept that objective measures can guide aggressive treatment to reach a defined optimal end point or target is a strategy that rheumatologists hopefully might now agree is critically important.