Demographic parameter, diagnostic tests, diagnoses and treatment of 76 juvenile patients with RMD with laboratory-proven SARS-CoV-2 infection
| Patients | Total cohort | Symptomatic | Asymptomatic |
| Total | 76 | 58 | 18 |
| Female, % | 52 | 55 | 44 |
| Age, median (IQR) | 14 (11–16.5) | 14 (12–17) | 12 (7–16) |
| Test method, n (%) | |||
| PCR | 54 (71) | 41 (71) | 13 (72) |
| Antigen test | 3 (4) | 3 (5) | 0 (0) |
| Antibody test | 19 (25) | 14 (24) | 5 (28) |
| Juvenile idiopathic arthritis, n (%) | 44 (58) | 33 (57) | 11 (61) |
| Oligoarthritis (persistent/extended) | 16 | 11 | 5 |
| Polyarthritis (RF negative/positive) | 17 | 15 | 2 |
| Enthesitis-related arthritis | 7 | 4 | 3 |
| Systemic juvenile idiopathic arthritis | 3 | 3 | 0 |
| Other arthritis | 1 | 0 | 1 |
| Autoinflammatory diseases, n (%) | 18 (24) | 18 (31) | 0 |
| FMF | 11 | 11 | 0 |
| NLRP3-associated autoinflammatory disease | 2 | 2 | 0 |
| PFAPA | 1 | 1 | 0 |
| TRAPS | 3 | 3 | 0 |
| DADA2 | 1 | 1 | 0 |
| Connective tissue disease, n (%) | 6 (8) | 3 (5) | 3 (17) |
| SLE | 3 | 2 | 1 |
| JDM | 1 | 0 | 1 |
| Sjögren’s syndrome | 1 | 1 | 1 |
| Scleroderma (localised) | 1 | 0 | 1 |
| Other, n (%) | 8 (11) | 4 (7) | 4 (22) |
| Behçet's disease | 1 | 1 | 0 |
| CRMO | 4 | 2 | 2 |
| SpA* | 1 | 1 | 0 |
| Sjögren‘s syndrome | 1 | 1 | 0 |
| Uveitis (idiopathic) | 2 | 0 | 2 |
| Treatment, n (%) | 66 (87) | 49 (84) | 17 (94) |
| Systemic glucocorticoids | 8 | 4 | 4 |
| Any DMARD | 58 | 49 | 9 |
| MTX | 18 | 13 | 5 |
| bDMARD | 31 | 27 | 4 |
| TNF-α antagonist | 19 | 17 | 2 |
| MTX+TNF-α antagonist | 4 | 4 | 0 |
| IL-6 blockade | 6 | 5 | 1 |
| IL-1 blockade | 4 | 4 | 0 |
| Baricitinib | 1 | 1 | 0 |
| Colchicine | 9 | 9 | 0 |
| Hydroxychloroquine | 7 | 4 | 3 |
| Mycophenolate mofetil | 3 | 2 | 1 |
| Sulfasalazine | 1 | 1 | 0 |
| Azathioprine | 2 | 2 | 0 |
(b)DMARD, (biological) disease-modifying antirheumatic drug; CRMO, chronic recurrent multifocal osteomyelitis; DADA2, deficiency of adenosine deaminase 2; FMF, familial Mediterranean fever ; IL, interleukin; JDM, juvenile dermatomyositis; MTX, methotrexate; PFAPA, periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis; RF, rheumatoid factor; SLE, systemic lupus erythematosus; SpA, spondylarthritis, the patient was older than 16 years at the time of diagnosis and therefore could not be classified as having enthesitis-related arthritis; TNF, tumour necrosis factor; TRAPS, TNF-receptor-associated periodic syndrome.