Table 4.

Multivariable-adjusted NAC-associated mortality risk stratified by ANA seropositivity^a

	ANA (+) a (n = 148)				ANA (−) (n = 145)
Characteristic	n	HR	p-value	95% CI	n	HR	p-value	95% CI
NAC exposure	33	0.51	0.01	0.30–0.87	25	1.26	0.45	0.69–2.32
IPAF diagnosis b	64	1.23	0.37	0.78–1.95	13	0.37	0.05	0.14–0.99
Immunosuppressant exposure c	35	0.85	0.54	0.50–1.43	34	1.32	0.32	0.77–2.28
Anti-fibrotic exposure d	20	0.67	0.4	0.27–1.70	22	0.16	0.002	0.05–0.51
GAP Score	148	1.41	< 0.001	1.23–1.61	144	1.27	0.005	1.08–1.50

Abbreviations: NAC N-acetylcysteine, ANA anti-nuclear antibody, IPAF interstitial pneumonia with autoimmune features, GAP gender, age, physiology

^aANA titer ≥1:320 or nucleolar or centromere staining pattern at any titer

^bCompared to IPF diagnosis

^cPrednisone, azathioprine or mycophenolate

^dPirfenidone or nintedanib