Background and aims: Information regarding autoimmune symptoms that do not meet the diagnostic criteria for connective tissue disease in patients with idiopathic pulmonary fibrosis (IPF) is limited. The aim of the present study was to investigate differences in the clinical characteristics and prognosis of IPF patients with and without autoimmune symptoms.
Methods: Consecutive patients diagnosed with IPF (N = 96) from January 2008 to December 2012 were included. We compared the clinical characteristics of patients with and without autoimmune symptoms. Survival was compared by log-rank and Cox proportional hazard analyses.
Results: Thirty-six (38%) patients reported autoimmune symptoms. There were no significant differences in clinical characteristics between those with and without autoimmune symptoms. Patients with autoimmune symptoms had a better survival rate than those without symptoms [hazard ratio (HR) 0.27; 95% confidence interval (CI) 0.09-0.82; P = 0.020]. After adjusting for age, gender and smoking status, the presence of autoimmune symptoms was associated with improved survival (HR 0.29, 95% CI 0.09-0.89; P = 0.032). However, after adjusting for other covariates, including per cent predicted forced vital capacity and high-resolution computed tomography total extent score, the presence of autoimmune symptoms did not influence survival (HR 0.49, 95% CI 0.15-1.61; P = 0.240). The median follow-up period for the studied cohort was 31.5 months.
Conclusion: It appears that autoimmune symptoms are associated with better prognosis among IPF patients. However, future studies are needed to validate our findings.
Keywords: autoantibodies; autoimmune; idiopathic pulmonary fibrosis; undifferentiated connective tissue.
© 2014 John Wiley & Sons Ltd.