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Irreversible joint damage can occur within months rather than years of the onset of rheumatoid arthritis.1 It is therefore important that these patients are diagnosed and treated as early as possible. To facilitate the early introduction of effective treatment, a rapid referral system is important. Throughout Europe, a number of centres have developed early synovitis clinics (ESCs) for this purpose. However, the diagnosis of early inflammatory arthritis (IA) is often difficult and confusing for the primary care doctor and experience suggests that the efficiency of ESCs is impaired by inappropriate referrals.2 Is this criticism justified? If general practitioners find it difficult to diagnose early IA, what about hospital specialists? In this short study we posed the question “Can rheumatologists agree on a diagnosis of IA in an ESC?”
Patients were recruited from primary care in the greater Belfast area (population ca 400 000). We randomly selected 24 patients who had been referred to an ESC in a Belfast teaching hospital and invited them to attend for outpatient assessment. Informed written consent was obtained from each patient before they took part in the study. Six hospital rheumatologists (two specialist registrars and four consultants) independently assessed 20 patients referred to an ESC by their primary care doctor. Patients were randomly assigned to each rheumatologist, who was asked to judge whether or not the patient currently had any type of IA. Before the study, the assessing rheumatologists had agreed on a definition of IA. Each assessment was conducted in a maximum of 15 minutes, but patients were not informed of their diagnosis until the final consultation, which included an additional 15 minutes to provide time to arrange a management plan for their problems.
Twenty four patients were invited to participate in the study and 20 consented to take part. Three patients failed to turn up for their outpatient appointment and one patient who did attend declined to take part in the study. There was complete agreement in the assessment of 14/20 patients (70%), 11 (55%) of whom were deemed to have IA (including RA, psoriatic arthritis, and reactive arthritis) and three (15%) who were not. In two cases (10%), only one rheumatologist diagnosed IA. In a further two cases (10%), only two specialists diagnosed IA and in the final two patients (10%), four of the six specialists diagnosed IA. In all cases where there was disagreement, the final assessor shared the majority opinion as to the correct diagnosis. The level of agreement between assessors was calculated using the κ statistic, where a value of 1.0 represents total agreement. The overall κ value for the six assessors was 0.68. Interestingly, the registrars had a higher level of agreement (κ 0.9) than the consultant rheumatologists (κ 0.6), though the difference was not statistically significant.
These results show that IA can be a difficult diagnosis to make in the setting of an ESC, even among experienced rheumatologists. Nevertheless, the level of agreement in this study compares favourably with that in other specialties such as radiology and ophthalmology.3 Given these findings, it is clearly important to keep an open mind about the diagnosis of IA in its early stages, especially where the clinical findings are equivocal. Careful follow up of such patients should be an important part of the work of any ESC.
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