High antinuclear antibody titer is associated with increased mortality risk in patients with idiopathic pulmonary fibrosis

Abstract

Idiopathic pulmonary fibrosis (IPF) is a diagnosis of exclusion, requiring that potential etiologies of interstitial lung disease be ruled out. Antinuclear antibody (ANA) testing is commonly performed in individuals with IPF, but the clinical significance of ANA positivity remains uncertain. A retrospective search identified 161 patients diagnosed with IPF between May 2010 and January 2021. Data on ANA titers at the time of diagnosis were available in all cases. Mean age of the patients was 66.4 ± 9.6 years; 70.8% were male. ANA titers were high (≥ 1:160) in 25.4% of the cohort. Baseline characteristics were comparable between those with high and low ANA titers. During follow-up (median 28 months), 93 patients (57%) died. On Cox proportional-hazards analysis with lung transplantation entered as a competing risk and adjusting for potential confounders (age, sex, and baseline forced vital capacity and diffusing lung capacity for carbon monoxide), ANA ≥ 1:160, as a dichotomized variable, was significantly associated with case-specific mortality (HR 2.25, 95% CI 1.14−4.42, P = 0.02) and older age (for each 10-year increment, HR 1.55, 95% CI 1.07−2.25, P = 0.02). High ANA titers appear to be associated with increased mortality in IPF. This finding emphasizes the potential prognostic value of ANA testing. Further studies are needed to validate these findings and explore their implications for patient management.