The nature of the onset of rheumatoid arthritis: a reassessment.

A total of 300 consecutive patients referred to a tertiary-care center and fulfilling the American Rheumatism Association criteria for definite-classical rheumatoid arthritis, (with a mean disease-duration of 10.3 +/- 9 years) were studied by structured interview and medical record review. The type of onset (rapid or insidious), type of joint involved (small, medium, large or combined joints) and pattern of joint involvement (monarticular, pauciarticular or polyarticular) at onset, and the interval between the first symptom and development of established disease were determined from the interview (based on the patient's memory). The onset was rapid in 46%. Initial involvement occurred in small joints in 31%, medium joints in 16%, large joints in 28% and combined sites in 25%. The pattern of joint involvement at onset was monarticular in 21%, pauciarticular in 44% and polyarticular in 35%. The time for disease to become established was less than 1 month in 25%, 1-6 months in 35%, 6-12 months in 14% and over 1 year in 26%. The monarticular pattern of onset was associated with slower development of established disease than the other patterns of joint involvement; polyarticular disease tended to be associated with polyarticular onset; involvement of large joints was associated with pauciarticular onset.