Rheumatoid arthritis is an autoimmune disease that can affect various organs, including the lungs, and lead to rheumatoid arthritis-interstitial lung disease (RA-ILD).

RA-ILD is responsible for increased mortality in rheumatoid arthristis (RA) patients.

The prevalence of RA-ILD varies according to the screening tool used.

The current gold standard is chest CT, but this is an expensive, time-consuming and irradiating examination, and recommendations on when and how often it should be performed are not clearly established.

Lung ultrasound (LUS) is an emerging tool for the detection of lung parenchymal damage, particularly in systemic scleroderma and idiopathic pulmonary fibrosis (IPF).

LUS is a non-irradiating, non-expensive examination that can be performed rapidly.

The aim of our study is to evaluate LUS as a screening tool for RA-ILD, in patients with risk factors for developing RA-ILD.

Patients with RA and who have risk factors for RA-ILD are regularly reassessed in a rheumatology day hospital.

As part of their routine follow-up, and given the absence of recommendations on screening for RA-ILD in this population, chest CT and PFT (pulmonary function tests) are regularly performed at the request of the rheumatologist.

Therefore, all patients meeting the inclusion criteria and having undergone chest CT and PFT in the 6 months preceding or following their rheumatology reassessment will be offered participation in the study.

Participation in the study does not alter the patient's usual follow-up.

Objective of the study: evaluate the sensitivity and specificity of thoracic ultrasound compare to the chest CT in patients with risk factors of developing RA-ILD.

Design: This is a non-interventional, prospective, single-center, multidisciplinary study.

Inclusion Criteria:

• Adult patient (age > 18 years) followed at CHU of Tours

• Diagnosis of rheumatoid arthritis validated according to ACR 2010 criteria, EULAR classification, regardless of time since diagnosis

• Patient who has had or will have a thoracic CT scan and PFT performed as part of routine care in the 6 months preceding or following inclusion

• Patient with at least two risk factors for developing RA-ILD among :

  • Male sex or
  • Active or former smoker assessed at 20 pack-year or
  • Age > 60 years or
  • Levels of RF≥3N (rheumatoid factor) and/or anti-CCP≥3N (antibodies against cyclic citrullinated peptides) at diagnosis or at any time during the course of the disease or
  • High RA activity score (DAS28>3.2)

Exclusion Criteria:

• Diagnosis of congenital lung disease
• Diagnosis of another autoimmune pathology associated with RA (overlap syndrome) linked to the development of ILD (interstitial lung disease) (systemic sclerosis, myositis, dermatomyositis, mixed connectivitis, systemic lupus erythematosus or other ANCA vasculitis, with the exception of secondary Gougerot-Sjögren's syndromes).
• Current or operated lung cancer
• Thoracic irradiation
• Thoracic transplant patients
• Previous invasive thoracic procedures
• Pathologies responsible for pleural thickening (silicosis, asbestosis, known pleural plaque, pleural sequelae of tuberculosis)
• Pregnant or breast-feeding women
• Patient under legal protection (guardianship, curatorship or safeguard of justice)
• Patient who has objected to data processing
• Parenchymal infection current or less than one month old prior to LUS examination
• Liquid or gaseous pleural effusion

Adult patients followed at CHU de Tours with a diagnosis of rheumatoid arthritis and with at least two risk factors for developing PR-PID