Clinical manifestation, prevalence and prognosis of sarcoid arthropathy a nationwide study: The Icelandic Sarcoidosis Study

Study objective: The Icelandic Sarcoidosis Study (ISS) contains all tissue-verified cases of sarcoidosis in Iceland since 1981. The present study has extended registration and verification to the start of 2004, thus covering over 23 years and a total of 234 cases. The aim of this study was to elucidate the prevalence, clinical manifestation and long-term prognosis of sarcoid arthritis in this unselected nationwide cohort. The presence of joint or muscle symptoms was registered in 20% of these cases. Methods: We used a questionnaire to register the lung and joint symptoms and all participants were offered a clinical evaluation with standardized interview and physical examination, including a count of the number of painful and/or inflamed joints. Results: Forty-seven (20%) of the 234 individuals in the ISS reported skeletal symptoms. In thirty-nine cases (17%) it was possible to confirm a history of inflammatory joint disorder. The mean age was 45 years: women 46 years (30-66), men 43 years (28-66). In 82% of the cases one or both ankles were involved. In 22 or 56% of the cases (13 female and 9 male) reliable data on the disease course were obtained; 87% of the patients had full recovery in less than 6 months, while 13% of the patients (all female) experienced chronic arthritic disease. Conclusions: Our nationwide-based data confirmed that around a fifth of all those diagnosed with sarcoidosis will develop joint symptoms associated with their sarcoidosis, most usually in the ankle. The prognosis is favourable, but a subgroup of female patients may develop chronic polyarthritis. It is urgent to study further in detail the risk factors for a chronic arthritic condition in sar-coidosis; thus, it would be possible to offer those at risk of arthritis modifying anti-rheumatic treatment in the early phase of their disease course.