Table 2.
Baseline characteristics of MDA5+ DM-ILD patients without and with SPM/P occurred within the first 3 months of ILD
| Characteristics | Without SPM/P n = 431 |
SPM/P n = 63 |
P-value |
|---|---|---|---|
| Demographic information | |||
| Male,n(%) | 137(31.7) | 34(53.9) | < 0.001 |
| Age on admission,y.o | 52(44–59) | 51(46–59) | 0.708 |
| Disease duration since first symptom of DM, months | 2.0(2.0–3.0) | 3.0(2.0–4.0) | 0.220 |
| Smoking history,n(%) | 48(11.1) | 10(15.8) | 0.275 |
| Clinical manifestations | |||
| RPILD,n(%) | 185(42.9) | 55(87.3) | < 0.001 |
| Fever,n(%) | 244(56.6) | 34(53.9) | 0.693 |
| Dysphagia,n(%) | 51(11.8) | 11(17.4) | 0.208 |
| Arthralgia,n(%) | 185(42.9) | 22(34.9) | 0.229 |
| Myalgia,n(%) | 119(27.6) | 10(15.8) | 0.048 |
| Muscle weakness,n(%) | 221(51.2) | 27(42.8) | 0.212 |
| Skin ulcer,n(%) | 80(18.5) | 12(19.0) | 0.926 |
| Gottorn'sign,n(%) | 323(74.9) | 51(80.9) | 0.299 |
| Heliotrope rash,n(%) | 338(78.4) | 52(82.5) | 0.454 |
| Periungual erythema,n(%) | 99(22.9) | 15(23.8) | 0.883 |
| Mechanic hands,n(%) | 143(33.1) | 15(23.8) | 0.136 |
| Laboratory tests | |||
| SF(ng/mL) | 970.8(390.3–1765.0) | 1,515.0(689.9–2764.3) | 0.001 |
| SF > 2000 ng/mL,n(%) | 76(17.6) | 26(41.2) | < 0.001 |
| LDH(U/L) | 319.0(246.0–424.0) | 449.0(298.0–597.0) | < 0.001 |
| LDH > 400U/L,n(%) | 90(20.8) | 30(47.6) | < 0.001 |
| ALT(IU/L) | 58(34–106) | 58(31–97) | 0.656 |
| Anti-MDA5 titer(RU/ml) | 160.0(119.4–191.3) | 150(122.4–188.8) | 0.593 |
| CRP elevation,n(%) | 111(25.7) | 31(49.2) | < 0.001 |
| Anti-Ro52 antibody positive,n(%) | 287(66.5) | 42(66.6) | 0.990 |
| Lymphocyte count < 0.8*109/L,n(%) | 250(58.0) | 44(69.8) | 0.074 |
| Pulmonary function | |||
| FVC_based stage,n(%) | < 0.001 | ||
| FVC% predicted ≥ 50% (Stage1) | 271(62.8) | 9(14.3) | |
| FVC% predicted < 50% (Stage2) | 87(20.1) | 18(28.5) | |
| Unable to perform PFTs (Stage3) | 73(16.9) | 36(57.1) | |
| Infection | |||
| Bacterial,n(%) | 62(14.3) | 18(28.5) | 0.004 |
| Aspergillus,n(%) | 32(7.4) | 12(19.0) | 0.002 |
| PJP,n(%) | 12(2.7) | 5(7.9) | 0.053 |
| CMV,n(%) | 60(13.9) | 18(28.5) | 0.003 |
Bold values indicate significance. MDA5,anti-melanoma differentiation-associated gene 5; CRP elevation was defined as C-reactive protein > 8 mg/L
DM dermatomyositis, ILD interstitial lung disease, SPM/P spontaneous pneumomediastinum/pneumothorax, RPILD rapid-progressive interstitial lung disease, FVC-Stage1 was defined as FVC% predicted ≥ 50%, FVC-Stage2 was defined as FVC% predicted < 50%, FVC-Stage3 was defined as unable to perform PFTs. RPILD rapid-progressive interstitial lung disease, LDH lactate dehydrogenase, SF serum ferritin, PJP Pneumocystis jirovecii pneumonia, CMV cytomegalovirus