Peer-review started: July 22, 2014
First decision: July 22, 2014
Revised: September 27, 2014
Accepted: December 10, 2014
Article in press: December 10, 2014
Published online: March 12, 2015
Rheumatoid arthritis (RA) is the most common chronic autoimmune inflammatory joint disease. RA-associated interstitial lung disease (RA-ILD) is a major extra-articular complication and causes symptoms that lead to a deterioration in the quality of life, high utilization of health resources, and an increased risk of earlier mortality. Early in the course of RA-ILD, symptoms are highly variable, making the diagnosis difficult. Therefore, a rational diagnostic strategy that combines an adequate clinical assessment with the appropriate use of clinical tests, including pulmonary function tests and high-resolution computed tomography, should be used. In special cases, lung biopsy or bronchioalveolar lavage should be performed to achieve an early diagnosis. Several distinct histopathological subtypes of RA-ILD are currently recognized. These subtypes also have different clinical presentations, which vary in therapeutic response and prognosis. This article reviews current evidence about the epidemiology of RA-ILD and discusses the varying prevalence rates observed in different studies. Additionally, aspects of RA-ILD pathogenesis, including the role of cytokines and other molecules such as autoantibodies, as well as the evidence linking several drugs used to treat RA with lung damage will be discussed. Some aspects of the clinical characteristics of RA-ILD are noted, and diagnostic strategies are reviewed. Finally, this article analyzes current treatments for RA-ILD, including immunosuppressive therapies and biologic agents, as well as other therapeutic modalities. The prognosis of this severe complication of RA is discussed. Additionally, this paper examines updated evidence from studies identifying an association between drugs used for the treatment of RA and the development of ILD.
Core tip: This review analyzes current evidence regarding the epidemiology, pathogenesis, diagnosis and treatment of interstitial lung disease associated with rheumatoid arthritis (RA-ILD). Data regarding differences in the prevalence of RA-ILD in different populations are presented. Updates regarding the pathogenesis of RA-ILD, including genetics, environmental factors, cytokines and autoantibodies, are presented. The paper also reviews the different tests used to diagnose RA-ILD, describes RA-ILD treatment, and discusses studies that were designed to identify a therapeutic response to immunosuppressive drugs or biological agents.