• NEED: The importance of an appropriate definition for the disease activity to specifically manage patients with AOSD is recognised
• AIM: The criteria for the assessment of disease activity for AOSD have to be valid, reliable, and easily transferable in any clinical setting
• SCOPE: The development of specific criteria for the assessment of disease activity should include a precise definition of the clinical features which could better describe the patient condition.

Points to Consider

1. Fever (being most frequent clinical sign of disease activity in AOSD) has to be considered as one of the variables of the core set. 
2. Skin rash, although evanescent, may occur at the onset of the disease and during its flares
3. Arthralgia and arthritis are seen in a large majority of patients with AOSD at the onset of the disease and during its flares
4. The systemic involvement of AOSD may affect different organs, resulting in secondary lymphoid structures enlargement and serositis, which can be observed in more severe patients
5. Hyperferritinaemia is the laboratory marker most frequently associated with AOSD onset and relapses
6. Increased levels of CRP and ESR, although nonspecific, are commonly detected during AOSD onset and may be helpful in identifying a clinical flare
7. Increased levels of liver enzymes are frequently associated with AOSD systemic involvement
8. Increased white blood cell count, mainly polymorphonuclear cells, is commonly detected at the onset of the disease and may be helpful in identifying a clinical flare
9. Patient global VAS may be a helpful criterion to assess AOSD disease flare
10. An objective definition of ‘remission’ is an important need, together with the definition of disease activity, to identify the clinical therapeutic target to be reached in patients with AOSD
11. The development of a disease-specific PRO may improve the management of AOSD by incorporating the patient perspective

This EULAR PtC exercise has successfully highlighted the many, impressive, but protean features that have defined AOSD since the original description by Bywaters in 1971 and Bujak, et al in 1973.  These PtC represent a consensus and preferred inclusion of criteria that could be developed into an “activity” or severity score.  That would be the logical next step.

(Editors comments: 1) Hyperferritinemia is not the most frequently found inflammatory marker in AOSD onset or relapses, as it is seen in roughly 50% of AOSD patients with active systemic disease.  Better performance is seen with elevated ESR or CRP, that can be seen in 85-95% of AOSD patients at the onset or during flares;  2) While PRO’s would be a very welcomed parameter to follow in AOSD, there is very little quality data regarding Patient Global VAS or any other disease specific PRO that would be useful in patient assessment or management. Nevertheless, a patient perspective on disease severity or impact would be welcomed. 3) Remission needs to be defined, with an emphasis on whether this is remission on therapy vs. off therapy and whether remission on therapy would be reasonably predictive of future remission off therapy, that would be sustained and long-lasting.)