Table 1.
Clinical and demographic characteristics of IIM patients and healthy controls: cross-sectional cohort.
| Parameters | IIM patients (n=277) | Healthy controls (n=157) | p-value |
|---|---|---|---|
| Sex: Female/Male, n (%) | 198 (71)/79 (29) | 92 (59)/65 (41) | 0.006 |
| Age, years | 56.5 (45.9 – 64.4) | 46.0 (34.0 – 60.0) | 0.001 |
| Clinical features | |||
| Disease duration, years | 1.7 (0.6 – 5.9) | ||
| IIM subtype, n (%): PM/DM/ | 104 (37.5)/104 (37.5)/ | ||
| CDM/IMNM | 42 (15)/27 (10) | ||
| IIM-associated symptoms, n (%): | |||
| MW/SR/MH/RP/ | 236 (85)/133 (48)/96 (35)/78 (28)/ | ||
| A/ILD/CI/D | 76 (27)/126 (45)/50 (18)/120 (43) | ||
| MITAX | 0.13 (0.08 – 0.21) | ||
| MYOACT | 0.05 (0.02 – 0.12) | ||
| MDI extent | 0.08 (0.03 – 0.14) | ||
| MDI severity | 0.03 (0.01 – 0.06) | ||
| MDI extended | 0.08 (0.00 – 0.13) | ||
| MMT-8 | 65.0 (55.0 – 74.0) | ||
| HAQ | 0.9 (0.3 – 1.5) | ||
| Laboratory features | |||
| Autoantibodies, n (%): | |||
| ANA/Ro-52/Jo-1/TIF1/PM-Scl/ | 124 (45)/80 (29)/64 (23)/21 (8)/29 (11)/ | ||
| Mi-2/Ro-60/HMGCR/SRP/U1RNP/MDA5/ | 20 (7)/18 (6.5)/14 (5)/10 (4)/9 (3)/6 (2.2)/ | ||
| La/PL-7/Ku/SAE/NXP2 | 4 (1.4)/3 (1.1)/2 (0.7)/2 (0.7)/1 (0.4) | ||
| CRP, mg/L | 2.5 (1.3 – 6.3) | ||
| CK, μkat/L | 2.6 (0.9 – 12.4) | ||
| LD, μkat/L | 4.8 (3.5 – 7.4) | ||
| Current treatment | |||
| Prednisone equivalent dose, mg/day | 20.0 (7.5 – 47.5) | ||
| GC/MTX/AZA/ | 227 (82)/83 (30)/22 (8)/ | ||
| CPA/CSA, n (%) | 1 (0.3)/5 (2) |
Data are presented as median (inter-quartile range) unless stated otherwise; A, arthritis; ANA, antinuclear antibodies; AZA, azathioprine; CDM, cancer-associated dermatomyositis; CI, cardiac involvement; CK, creatine kinase; CPA, cyclophosphamide; CRP, C-reactive protein; CSA, cyclosporin A; D, dysphagia; DM, dermatomyositis; GC, glucocorticoids; HAQ, Health Assessment Questionnaire; HMGCR, anti-3-hydroxy-3-methylglutaryl-CoA reductase; IIM, idiopathic inflammatory myopathy; ILD, interstitial lung disease; IMNM, immune-mediated necrotizing myopathy; Jo-1, anti-histidyl-tRNA synthetase; Ku, anti-Ku (against the nuclear DNA-dependent protein kinase subunit); La, anti-La (against La(SS-B), a nuclear 47 kD phosphoprotein, associated with small RNA synthesized by RNA polymerase III); LD, lactate dehydrogenase; MDA5, anti-CADM-140 (melanoma differentiation-associated gene 5); MDI, Myositis Damage Index; MH, mechanic’s hands; Mi-2, antinuclear helicase 218/240 kDa; MITAX, Myositis Intention to Treat Activity Index; MMT-8, Manual Muscle Testing of eight muscles; MTX, methotrexate; MW, muscle weakness; MYOACT, Myositis Disease Activity Assessment visual analogue scale; NXP2, anti-NXP2 (nuclear matrix protein); PL-7, anti-threonyl-tRNA synthetase; PM, polymyositis; PM-Scl, anti-Pm-Scl (anti-core complex 11-16 proteins); Ro, anti-Ro (52/60kDa, against cytoplasmic RNA and associated peptides); RP, Raynaud’s phenomenon; SAE, anti-SUMO1 (small ubiquitin-like modifier 1) activating enzyme; SR, skin rash; SRP, anti-signal recognition particles; TIF1, anti-TIF1 (transcriptional intermediary factor-1); U1RNP, anti-U1-RNP (ribonucleoprotein).