Abstract

Idiopathic pulmonary fibrosis (IPF) is a diagnosis of exclusion, after eliminating potential etiologies of interstitial lung disease. While individuals with IPF are routinely tested for antinuclear antibody (ANA), the clinical significance of ANA positivity in IPF is not conclusive. In a retrospective search, we identified 161 patients diagnosed with IPF from May 2010 through January 2021, and with ANA titers. The mean age was 66.4±9.6 years, 70.8% were males. High (?1:160) ANA titers were found in 25.4% of the patients. Age, gender, comorbidities, and pulmonary function tests were comparable between those with high and low ANA titers. During a median 28 months, 93 (57%) patients died. We performed a Cox proportional-hazards model with regression of lung transplantation a competing risk and including the potential confounders (age, sex, and baseline values of forced vital capacity and diffusing lung capacity for carbon monoxide). ANA ?1:160 as a dichotomized variable was associated with case-specific mortality (hazard ratio (HR) 2.25, 95% confidence interval (CI) 1.14?4.42, p = 0.02) and with older age (for each 10-year increment, HR 1.55, 95% CI 1.07?2.25, p = 0.02). In conclusion, high ANA titer was found to be associated with increased mortality among patients with IPF.