INTRODUCTION: Some patients with interstitial pneumonia with autoimmune features (IPAF) will develop connective tissue disease (CTD) in the future. It is of key importance to assess the prevalence of conversion to CTDs and mortality in patients with IPAF compared to connective tissue disease-associated interstitial lung disease (CTD-ILD). Another issue is the unknown likelihood of developing cancer in these groups of patients, which is known to be more common in idiopathic pulmonary fibrosis (IPF) ? another fibrosing ILD ? than in the general population. However, there is still little prospective research on the issues.

OBJECTIVES: The aim of this study is to evaluate the conversion rate to CTDs in IPAF patients and to assess mortality and risk of developing cancer in IPAF and CTD-ILD groups. We present our preliminary results while the study is still ongoing.

METHODS: We prospectively enrolled patients with IPAF, CTD-ILD and CTD-non-ILD. They have been followed by both rheumatologists and pulmonologists. The study started in December 2020, with a follow-up of 12 months.

RESULTS: We recruited 30 patients in each group: IPAF, CTD-ILD and CTD-non-ILD. We have completed follow-up in 23 patients with IPAF and 27 with CTD-ILD. We noted 2 deaths (unrelated to cancer) in each group. 1 patient in each group developed a neoplastic process. 2 patients with IPAF met the criteria for CTD during follow-up.

CONCLUSIONS: Only a small percentage of patients with IPAF developed CTD during follow-up. Mortality and the likelihood of developing cancer in IPAF and CTD-ILD patients seemed to be high.