Relation between pulmonary function tests and ultrasonographic changes of asymptomatic anterior chest wall joints in rheumatoid arthritis patients

Abstract
Background
Ultrasonography can detect different changes in anterior chest wall (ACW) joints in patients with rheumatoid arthritis (RA) even before being clinically manifested. Airways, pleura, lung parenchyma, and vascular compartment all may be attacked by RA. This study was aiming at detecting the relation between ultrasonographic changes of asymptomatic ACW joints and pulmonary function tests (PFTs) in patients with RA.

Results
US detected subclinical changes of ACW joints in (74.2%) of RA patients with significant difference between total US changes in RA (74.2%) and control (21.2%) (p < 0.001). MSJ ankylosing and erosions were highly associated with limited chest expansion in RA group (P <0.001). Restrictive PFTs were associated with SCJ synovitis (p < 0.05), SCJ PD activity (p < 0.05), SCJ erosions (0.02), and highly associated with MSJ ankylosing and erosions (p < 0.001).

Conclusions
This study demonstrated that ultrasonographic subclinical changes in ACW joints are associated with restrictive pattern by spirometry and limited chest expansion in RA patients.

Trial registration
ClinicalTrials.gov Identifier: NCT05119491. Registered 15 November 2021—retrospectively registered.