The evaluation of myocarditis in patients with Still's disease; clinical findings from the multicentre international AIDA Network Still's Disease Registry.

Objective: To evaluate the cardiac involvement in patients with Still's disease with a focus on myocarditis included in the multicenter AIDA (AutoInflammatory Disease Alliance) network Still's disease registry. To exploit the predictive factors for myocarditis in deriving a clinical risk patient profile for this severe manifestation.

Methods: A multicenter observational study was built up assessing consecutive patients with Still's disease characterized by the cardiac involvement among those included in the AIDA Network Still's Disease Registry. The cardiac involvement was defined according to the presence of pericarditis, tamponade, myocarditis, and/or aseptic endocarditis.

Results: In total, 73 patients with Still's disease and cardiac involvement were assessed (mean age 36.3±19.9 years, 42.5% male sex); out of them, 21.9% were children. The most common cardiac manifestation was the pericarditis in 90.4% of patients, 26.0% presented with myocarditis, and less frequently endocarditis (2.7%) and tamponade (1.4%). Comparing clinical features of patients with myocarditis than others, significantly increased frequencies of skin rash, and pleuritis as well as higher values of systemic score were recognised. Furthermore, an enhanced mortality rate was registered in patients with myocarditis. In regression models, the skin rash and the systemic score independently predicted the myocarditis.

Conclusion: The characteristics of patients with Still's disease and cardiac involvement were assessed in the AIDA network. The most common feature was the pericarditis but also a more severe clinical picture was reported in patients with myocarditis. The latter was associated with increased mortality rate and with higher systemic score, identifying patients to be carefully managed.