Parameter | Anti-synthetase | IPF | P value |
Total n=76 | Total 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- smoker | 25%–33% | 46%–59% | 0.004* |
Current | 4%–5% | 2%–3% | Ex/current vs never |
Never | 44%–58% | 29%–37% | |
Unknown | 2%–3% | 1%–1% | |
Neutrophil: lymphocyte ratio (IQR) | 5.68 (3.52–9.30), n=73 | 2.50 (1.95–3.60), n=73 | <0.0001 |
MRC dyspnoea scale (IQR) | 2 (2–3), n=65 | 3 (2–4), n=73 | 0.073 |
Auto-immune profile | |||
ANA positivity (n, %) | 16, 23%, n=71 | 26, 39%, n=67 | 0.038 |
Cytoplasmic staining mentioned on HEp 2 IF report (n, %) | 29, 71% n=41 | 0, 0%, n=47 | <0.0001* |
Baseline Lung function parameters | |||
FEV1 actual (L) (IQR) | 1.96 (1.550–2.57), n=75 | 2.14 (1.65–2.48), n=78 | 0.464 |
FEV% predicted (IQR) | 69 (56–80) | 90 (79–99) | <0.0001 |
FVC actual (L) (IQR) | 2.53 (1.83–3.10), n=75 | 2.76 (2.07–3.21), n=78 | 0.521 |
FVC % predicted | 73 (63–84) | 87 (74–97) | 0.0002 |
TLCO (L) (IQR) | 4.34 (3.26–5.71), n=63 | 3.84 (2.97–4.63), n=69 | 0.018 |
TLCO % predicted (IQR) | 50 (41–64) | 50 (39–62) | 0.429 |
6MWT | |||
Distance (m) (IQR) | 360 (285–428), n=40 | 335 (240–380), n=70 | n/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, %) | |||
cNSIP | 14%–18% | – | – |
fNSIP | 24%–32% | – | – |
OP | 13%–17% | – | – |
cNSIP/OP overlap | 11%–14% | – | – |
fNSIP/OP overlap | 6%–8% | – | – |
DAD | 1%–1% | – | – |
fNSIP/UIP | 2%–3% | – | – |
Probable UIP | – | 26%–33% | <0.0001* |
Definite UIP | 4%–5% | 47%–60% | |
Indeterminate | 1%–1% | 5%–6% | 0.210* |
Extent of ILD on HRCT | n=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.