Clinical features and laboratory/imaging findings in patients with SARS-CoV-2-associated inflammatory joint disease
| Whole cohort (n=35) | Early onset (≤2 weeks) (n=12) | Late onset (>2 weeks) (n=23) | P value early vs late onset | |
| Age, years | 52.4±13.3 | 50.3±9.4 | 53.5±15.0 | 0.44 |
| Female sex, n (%) | 23 (65.7) | 7 (58.3) | 16 (69.6) | 0.71 |
| Current smokers, n (%) | 6 (17.1) | 1 (8.3) | 5 (21.7) | 0.64 |
| Symptomatic COVID-19, n (%) | 29 (82.9) | 12 (100) | 17 (73.9) | 0.07 |
| COVID-19 symptoms | ||||
| Fever, n (%) | 26 (74.3) | 10 (83.3) | 16 (69.6) | 0.45 |
| Cough, n (%) | 17 (48.6) | 5 (41.7) | 12 (52.2) | 0.72 |
| Dyspnoea, n (%) | 8 (22.9) | 4 (33.3) | 4 (17.4) | 0.40 |
| Arthralgia and/or myalgia, n (%) | 22 (62.9) | 11 (91.7) | 11 (47.8) | 0.01 |
| Taste and/or smell loss, n (%) | 8 (22.9) | 4 (33.3) | 4 (17.4) | 0.40 |
| Severe COVID-19*, n (%) | 3 (8.6) | 1 (8.3) | 2 (8.7) | 1.00 |
| Evidence of SARS-CoV-2 infection | ||||
| RT-PCR on nasopharyngeal swab, n (%) | 32 (91.4) | 12 (100) | 20 (86.9) | 0.54 |
| SARS-CoV-2 specific IgM, n (%) | 3 (8.6) | 0 (0) | 3 (13.0) | 0.27 |
| COVID-19 treatment | ||||
| Paracetamol/NSAIDs, n (%) | 21 (60.0) | 10 (83.3) | 11 (47.8) | 0.07 |
| Glucocorticoids, n (%) | 11 (31.4) | 6 (50) | 5 (21.7) | 0.13 |
| Hydroxychloroquine, n (%) | 1 (2.9) | 1 (8.3) | 0 (0) | 0.34 |
| Low-molecular-weight heparin, n (%) | 5 (14.3) | 1 (8.3) | 4 (17.4) | 0.64 |
| Antibiotics and/or antivirals, n (%) | 4 (11.4) | 0 (0) | 4 (17.4) | 0.27 |
| Time between COVID-19 diagnosis and arthritis onset, days | 23.7±17.0 | 6.3±3.3 | 32.9±13.7 | <0.0001 |
| Pattern of joint involvement | ||||
| Asymmetric monoarthritis or oligoarthritis, n (%) | 18 (51.4) | 3 (25.0) | 15 (65.2) | 0.03 |
| RA-like polyarthritis, n (%) | 7 (20.0) | 5 (41.7) | 2 (8.7)† | 0.03 |
| PMR-like, n (%) | 4 (11.4) | 1 (8.3) | 3 (13.0)‡ | 1.00 |
| Predominantly axial, n (%) | 4 (11.4) | 3 (25.0)§ | 1 (4.3) | 0.11 |
| Enthesitis, n (%) | 2 (5.7) | 0 (0) | 2 (8.7) | 0.54 |
| US or MRI confirmed inflammation, n (%) | 21 (60.0) | 5 (41.7) | 16 (69.6) | 0.15 |
| RF positive, n (%)¶ | 1 (3.4) | 1 (12.5) | 0 (0) | 0.27 |
| ACPA positive, n (%)¶ | 0 (0) | 0 (0) | 0 (0) | N/A |
| ANA positive, n (%)¶ | 6 (22.2) | 2 (25.0) | 4 (21.0) | 1.00 |
| HLA-B27 positive, n (%)¶ | 1 (7.7) | 0 (0) | 1 (9.1) | 1.00 |
| ESR, mm/h | 31.3±18.3 | 24.9±17.8 | 34.6±18.1 | 0.14 |
| CRP, mg/dL | 2.34±2.58 | 2.74±2.50 | 2.14±2.65 | 0.51 |
| Treatment | ||||
| NSAIDs, n (%) | 25 (71.4) | 9 (75.0) | 16 (69.6) | 1.00 |
| Glucocorticoids, n (%) | 16 (45.7) | 5 (41.7) | 11 (47.8) | 1.00 |
| DMARDs, n (%)** | 6 (17.1) | 2 (16.7) | 4 (17.4) | 1.00 |
| Follow-up duration, weeks | 10.4 9.8 | 10.3±11.2 | 10.5±9.2 | 0.95 |
| Outcome | ||||
| Improved, n (%) | 10 (28.6) | 4 (33.3) | 6 (26.1) | 0.71 |
| Recovered, n (%) | 8 (22.9) | 2 (16.7) | 6 (26.1) | 0.68 |
| Relapsed, n (%) | 4 (11.4) | 1 (8.3) | 3 (13.0) | 1.00 |
| Active, n (%) | 12 (34.4) | 5 (41.7) | 7 (30.4) | 0.71 |
| N/A, n (%) | 1 (2.9) | 0 (0) | 1 (4.3) | 1.00 |
*Severe COVID-19 was defined as previously described as the presence of dyspnoea, respiratory rate of 30 or more breaths/min, blood oxygen saturation of 93% or less and ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2:FiO2) of less than 300 mm Hg, or infiltrates in more than 50% of the lung field (JAMA 2020 Apr 7;323(13):1239–42).
†Two out of two patients had polyarthritis affecting predominantly large joints.
‡One out of three patients with PMR presented with concurrent giant cell arteritis.
§Two out of three patients had concurrent peripheral involvement of metacarpophalangeal and proximal interphalangeal joints.
¶RF and ACPA were obtained in 29 out of 35 patients (8 in early onset and 21 in late onset group, respectively), ANA in 27 out of 35 patients (8 in early onset and 19 in late onset group, respectively), HLA-B27 in 13 out of 35 patients (2 in early onset and 11 in late group, respectively).
**Either methotrexate, sulfasalazine or hydroxychloroquine.
ACPA, anticitrullinated protein antibody; ANA, antinuclear antibodies; CRP, C reactive protein; DMARDs, disease-modifying antirheumatic drugs; ESR, erythrocyte sedimentation rate; HLA, human leukocyte antigen; N/A, not available; NSAIDs, non-steroidal anti-inflammatory drugs; PMR, polymyalgia rheumatica; RA, rheumatoid arthritis; RF, rheumatoid factor; RT-PCR, real-time PCR; US, ultrasonography.