Table 1

Baseline demographics of patients with anti-synthetase syndrome (ASyS) and idiopathic pulmonary fibrosis (IPF)

ParameterAnti-synthetaseIPFP value
Total n=76Total n=78
Demographics
 Age years (IQR)57 (47–65) (n=76)77 (73–82)<0.001
 Male gender (n, %)33%–43%52%–67%0.006*
 Smoking status (n, %)
  Ex- smoker25%–33%46%–59%0.004*
  Current4%–5%2%–3%Ex/current vs never
  Never44%–58%29%–37%
  Unknown2%–3%1%–1%
 Neutrophil: lymphocyte ratio (IQR)5.68 (3.52–9.30), n=732.50 (1.95–3.60), n=73<0.0001
 MRC dyspnoea scale (IQR)2 (2–3), n=653 (2–4), n=730.073
Auto-immune profile
 ANA positivity (n, %)16, 23%, n=7126, 39%, n=670.038
 Cytoplasmic staining mentioned on HEp 2 IF report (n, %)29, 71% n=410, 0%, n=47<0.0001*
Baseline Lung function parameters
 FEV1 actual (L) (IQR)1.96 (1.550–2.57), n=752.14 (1.65–2.48), n=780.464
 FEV% predicted (IQR)69 (56–80)90 (79–99)<0.0001
 FVC actual (L) (IQR)2.53 (1.83–3.10), n=752.76 (2.07–3.21), n=780.521
 FVC % predicted73 (63–84)87 (74–97)0.0002
 TLCO (L) (IQR)4.34 (3.26–5.71), n=633.84 (2.97–4.63), n=690.018
 TLCO % predicted (IQR)50 (41–64)50 (39–62)0.429
6MWT
 Distance (m) (IQR)360 (285–428), n=40335 (240–380), n=70n/s
 Baseline oxygen saturations % (IQR)95 (94–97)94 (92–96)n/s
 Minimum oxygen saturation % (IQR)89 (87–91)88 (83–92)n/s
HRCT pattern at presentation (n, %)
 cNSIP14%–18%
 fNSIP24%–32%
 OP13%–17%
 cNSIP/OP overlap11%–14%
 fNSIP/OP overlap6%–8%
 DAD1%–1%
 fNSIP/UIP2%–3%
 Probable UIP26%–33%<0.0001*
 Definite UIP4%–5%47%–60%
 Indeterminate1%–1%5%–6%0.210*
Extent of ILD on HRCTn=62
 <20%32
 ≥20%30
Patients presenting initially to respiratory services (n,%)52%–68%78%–100%
  • P value <0.05 deemed statistically significant, Mann-Whitney U test for comparison of two groups.

  • *Fishers exact test used.

  • %, percentage; ANA, anti-nuclear antibodies; cNSIP, cellular NSIP; DAD, diffuse alveolar damage; fNSIP, fibrotic non-specific interstitial pneumonia; FVC, forced vital capacity; HRCT, high-resolution CT; HEp2 IF, Hep-2 cell immunofluorescence; ILD, interstitial lung disease; L, litres; m, metres; 6MWT, 6 min walk test; n, number; OP, organising pneumonia; TLCO, transfer factor for carbon monoxide; UIP, usual interstitial pneumonia.