Article Figures & Data
Figures
- Figure 1.
Kaplan-Meier survival curves of patients with SSc-PM and patients with SSc. SSc: systemic sclerosis; SSc-PM: SSc/polymyositis overlap.
Tables
- Table 1.
Clinical characteristics of study population. Values are n (%) unless otherwise specified.
Characteristics Total, n = 420 SSc-PM, n = 24 SSc, n = 396 p, SSc-PM vs SSc Age, yrs, mean (SD) 50 (13.1) 52 (12.1) 50 (13.2) 0.28 Female 273/420 (65) 13/24 (54) 260/396 (66) 0.25 Type SSc, lcSSc/dcSSc 306 (73)/114 (27) 19 (79)/5 (21) 287 (73)/109 (27) 0.47 Disease duration since SSc, yrs, median (IQR) 7.8 (3.9–14.1) 6.3 (4.2–12.9) 7.8 (3.9–14.1) 0.85 Disease duration since PM, yrs, median (IQR) — 5.7 (3.8–12.9) — — Mortality 73/420 (17) 8/24 (33) 65/396 (16) 0.048 SSc features RP 400/420 (95) 21/24 (88) 379/396 (96) 0.098 Digital ulcers 169/420 (40) 5/24 (21) 161/395 (41) 0.046 mRSS, median (IQR) 7/386 (4–12) 6/15 (5–11) 7/371 (4–12) 0.96 Serology ANA 318/420 (76) 24/24 (100) 294/396 (74) 0.004 Anticentromere 78/414 (19) 2/18 (11) 76/396 (19) 0.55 Antitopoisomerase I 86/416 (21) 0/20 (0) 86/396 (22) 0.019 Internal organ involvement ILD 156/429 (37) 14/24 (58) 142/396 (36) 0.027 HRCT fibrosis 185/364 (51) 15/18 (83) 170/346 (49) 0.005 X-thorax fibrosis 61/414 (15) 6/20 (30) 55/394 (14) 0.096 TLC ≤ 70% of predicted 71/273 (26) 3/20 (15) 68/253 (27) 0.24 TLCO ≤ 70% of predicted 276/363 (76) 16/16 (100) 260/347 (75) 0.016 FEV1 ≤ 70% of predicted 98/385 (25) 6/22 (27) 92/363 (25) 0.84 Diastolic dysfunction, cardiac US153/371 (41) 7/19 (37) 146/352 (42) 0.69 PH suspicion by cardiac US 92/372 (25) 3/20 (15) 89/352 (25) 0.43 PH by cardiac catheterization 57/187 (31) 0/5 (0) 57/182 (31) 0.33 Renal crisis 18/420 (4) 1/24 (4) 17/396 (4) 1.0 SSc: systemic sclerosis; PM: polymyositis; lcSSc: limited cutaneous SSc; dcSSc: diffuse cutaneous SSc; IQR: interquartile range; RP: Raynaud phenomenon; mRSS: modified Rodnan skin score; ANA: antinuclear antibody; ILD: interstitial lung disease; HRCT: high-resolution computed tomography; TLC: total lung capacity of pulmonary function test; TLCO: transfer factor of the lung for carbon monoxide; FEV1: forced expiratory volume in 1 s; US: ultrasound; PH: pulmonary hypertension.
Characteristics n SSc-PM, n = 24 Necrotic muscle fibers 24 23 (96) Lymphocytic infiltrates 24 15 (63) Positive MHC class I staining 12 11 (92) Inflammation* 24 19 (79) MAC staining 10 5 (50) Fibrosis 19 5 (26) Presence of COX-negative fibers 10 3 (30) Presence of CD8-positive T cells 12 8 (67) ↵* Inflammation is defined as positive MHC class I staining or/and presence of lymphocytic infiltrates. SSc: systemic sclerosis; PM: polymyositis; MAC: membrane attack complex; COX: cytochrome oxidase.
Characteristics β HR 95% CI p Unadjusted model SSc-PM overlap diagnosis 0.87 2.40 1.15–5.02 0.02 Adjusted model SSc-PM overlap diagnosis 0.85 2.34 1.09–5.02 0.029 Age at diagnosis, yrs 0.08 1.08 1.05–1.10 < 0.001 mRSS 0.05 1.05 1.02–1.08 < 0.001 dcSSc involvement 0.46 1.59 0.87–2.91 0.14 Male 0.43 1.53 0.95–2.47 0.08 SSc: systemic sclerosis; PM: polymyositis; mRSS: modified Rodnan skin score; dcSSc: diffuse cutaneous SSc.
