[Diagnosis and course of early arthritis; study in a specialized clinic for early arthritis]

To investigate the occurrence, diagnosis and course of all new inflammatory arthropathies seen in a special Early Arthritis Clinic (EAC).

Prospective cohort study.

Academic Medical Hospital, Leiden, The Netherlands.

An Early Arthritis Clinic (EAC) was started in the outpatient clinic of rheumatology of Leiden University Hospital for diagnostic work-up according to protocol of patients with recent-onset arthritis. Inclusion criteria were: active arthritis with onset < 2 years without traumatic aetiology and no referral for a second opinion.

In the first 18 months 276 patients were sent to the EAC, 212 met the inclusion criteria. After 2 weeks the following diagnoses were made: rheumatoid arthritis (RA) (58; 28%), psoriatic arthritis (8; 4%), reactive arthritis (11; 5%) sarcoidosis (9; 4%), crystal arthritis (30; 14%), osteoarthritis (8; 4%), other diagnosis (18; 8%). The remaining 70 patients (33%) were classified as arthritis e causa ignota (e.c.i.). After follow-up, the first diagnoses changed in 27 (12%) patients, of whom 20 patients originally had had the diagnosis of arthritis e.c.i. Persistent arthritis was found in 90% of RA and in 35% of arthritis e.c.i. Other forms of arthritis seldom showed persistent activity.

In the EAC, RA, arthritis e.c.i. and crystal arthritis were seen most often. Almost all RA patients showed persistent arthritis, as against only a third of those with arthritis e.c.i. Because of the early diagnosis treatment could start early in patients with joint disease entailing irreversible joint destruction.