Usual interstitial pneumonia in rheumatoid arthritis-associated interstitial lung disease

TLDR

Interstitial lung disease frequently occurs in rheumatoid arthritis, but prognostic factors remain poorly understood. The study aimed to determine whether a usual interstitial pneumonia pattern on high‑resolution CT predicts prognosis in RA‑ILD. Retrospective analysis of 82 RA‑ILD patients and 51 idiopathic pulmonary fibrosis controls examined the association between definite UIP pattern on CT and survival. A definite UIP pattern was found in 24 % of RA‑ILD patients and was linked to poorer survival (median 3.2 vs 6.6 years, HR 2.3), comparable to idiopathic pulmonary fibrosis, with traction bronchiectasis and honeycomb fibrosis also predicting worse outcomes, while female sex and higher DLCO predicted better survival.

Abstract

Interstitial lung disease is a common manifestation of rheumatoid arthritis; however, little is known about factors that influence its prognosis. The aim of the present study was to determine whether or not the usual interstitial pneumonia pattern found on high-resolution computed tomography (HRCT) is of prognostic significance in rheumatoid arthritis-associated interstitial lung disease (RA-ILD). Patients with RA-ILD were identified retrospectively (n = 82). The relationship of a definite usual interstitial pneumonia pattern on HRCT to survival was determined and compared to that in a cohort of patients with radiologically diagnosed idiopathic pulmonary fibrosis (n = 51). A definite usual interstitial pneumonia pattern was seen in 20 (24%) out of 82 patients with RA-ILD. These patients showed worse survival than those without this pattern (median survival 3.2 versus 6.6 yrs), and a similar survival to those with idiopathic pulmonary fibrosis. On multivariate analysis, a definite usual interstitial pneumonia pattern on HRCT was associated with worse survival (hazard ratio of 2.3). Analysis of specific HRCT features demonstrated that traction bronchiectasis and honeycomb fibrosis were associated with worse survival (hazard ratio of 2.6 and 2.1, respectively). Female sex (hazard ratio of 0.30) and a higher baseline diffusing capacity of the lung for carbon monoxide (hazard ratio of 0.96) were associated with better survival. A definite usual interstitial pneumonia pattern on HRCT has important prognostic implications in RA-ILD.