Prevalence, imaging patterns and risk factors of interstitial lung disease in connective tissue disease: a systematic review and meta-analysis.

Introduction: Interstitial lung disease (ILD) is a frequent manifestation of connective tissue disease (CTD) with substantial variability in prevalence and outcomes reported across CTD subtypes. This systematic review summarises the prevalence, risk factors and ILD patterns on chest computed tomography of CTD-ILD.
Methods: A comprehensive search was performed in Medline and Embase to identify eligible studies. Meta-analyses were completed using a random effects model to determine the pooled prevalence of CTD-ILD and ILD patterns.
Results: 11 582 unique citations were identified with 237 articles included. Pooled prevalence of ILD was 11% in rheumatoid arthritis (95% CI 7-15%), 47% in systemic sclerosis (44-50%), 41% in idiopathic inflammatory myositis (33-50%), 17% in primary Sjögren's syndrome (12-21%), 56% in mixed connective tissue disease (39-72%) and 6% in systemic lupus erythematosus (3-10%). Usual interstitial pneumonia was the most prevalent ILD pattern in rheumatoid arthritis (pooled prevalence of 46%), while nonspecific interstitial pneumonia was the most common ILD pattern in all other CTD subtypes (pooled prevalence range 27-76%). Across all CTDs with available data, positive serology and higher inflammatory markers were risk factors for development of ILD.
Discussion: We identified substantial variability in ILD across CTD subtypes suggesting that CTD-ILD is too heterogenous to be considered a single entity.
Competing Interests: Conflict of interest: G.M. Joy has nothing to disclose. Conflict of interest: O.A. Arbiv has nothing to disclose. Conflict of interest: C.K. Wong has nothing to disclose. Conflict of interest: S.D. Lok has received fees, honoraria, or contracts from University of Saskatchewan CoM, Boehringer Ingelheim, Roche, and AstraZeneca unrelated to this work. Conflict of interest: N.A. Adderley has nothing to disclose. Conflict of interest: K.M. Dobosz has nothing to disclose. Conflict of interest: K.A. Johannson has received fees, honoraria, or contracts from Three Lakes Foundation, Chest Foundation, University of Calgary CSM, University Hospital Foundation, Boehringer Ingelheim, Hoffman-La Roche Ltd, Pliant Therapeutics, Thyron SAB, and PFOX trial all unrelated to this work. Conflict of interest: C.J. Ryerson has received fees, honoraria, or contracts from Boehringer Ingelheim, Hoffman-La Roche Ltd, Pliant Therapeutics, AstraZeneca, Veracyte, Ensho, Cipla Ltd, all unrelated to this work.
(Copyright ©The authors 2023.)