Developments in epidemiological studies on rheumatoid arthritis

A review of assignment criteria for rheumatoid arthritis

A comparative evaluation of existing assignment criteria for rheumatoid arthritis has been undertaken as a preliminary to exploring how simpler and more efficient standards could be developed. The performances of alternative formulations of individual criteria have been evaluated, and the various criteria have been assessed singly and in combination. The two individual criteria giving rise to the greatest difficulty are morning stiffness and pain and/or tenderness, with its optional formulation. An alternative criterion, pain in at least three sites on squeezing the MCP or MTP joints, performed well. Taken in combination, better epidemiological discrimination was achieved with the threshold for the 1958 ARA criteria midway between 'definite' and 'classical' disease, with six criteria fulfilled. Most of the discriminatory power of these criteria stemmed from inclusion of radiographic and serological characteristics, which is scarcely surprising. The Rome criteria for Inactive RA and the New York criteria for RA, which were derived from them, achieved better discrimination, which suggests ways in which improvements in assignment criteria might be approached. The 1987 revision of the ARA criteria achieves disappointingly little, as important difficulties have not been resolved.

Health care for rheumatic disorders in a Swedish county

Utilization of rheumatological care by individual patients was studied in a Swedish county at all levels of the health care system. Calculated per population at risk, 0.6--0.8% per year were seen for rheumatoid arthritis. Of these, 35--81% were patients at the rheumatology department, varying according to distance of residence from the university hospital. The number of patients with other inflammatory diseases was, however, larger in primary care than in the specialist department. Only a minor part of the total care for rheumatic disorders (Chapt. XIII of ICD) in the county was provided by the rheumatology department. Back disorders constituted the largest diagnostic group of rheumatic disorders in primary care. During a period of one year a total of 12--14% of the population had contact with primary care, of the district hospital and/or the rheumatology department, because of rheumatic disorders. The results show the value of epidemiological studies to follow the development of and to define the future objectives of rheumatological care.