Methodological problems--juvenile chronic arthritis

This group of diseases comprises a heterogeneous syndrome with several characteristics different from adult rheumatoid arthritis. They are characterized by joint swelling, pain/tenderness, heat and limitation of motion with or without several extra-articular manifestations. The natural course is fluctuating. There is no uniform disease course. The prognosis is better for children than adults with rheumatic disorders. The etiology is partly known and the pathogenesis unclear. There are no uniformly accepted diagnostic criteria. Patient materials studied need therefore be described in detail. The methods used for evaluation of disease and functional activities are crucial. The statistical methods, ethical problems including consent/assent are highly relevant. The management including drug therapy, drug handling and compliance need also to be considered. Due to relative rareness of the syndrome, preferably a few investigators that think alike need to collaborate for more efficient and ethically sound investigations of such patients.