I67. Drug-Induced Interstitial Lung Disease in Patients With RA

Abstract

RA is associated with an increased risk of serious pulmonary infection. Most observational studies have demonstrated a greater than 2-fold increased risk of serious pulmonary infection in RA. Pulmonary infection is the most prevalent infection associated with RA. There are a number of component risk factors for chronic pulmonary infection in RA: (i) drug therapy; (ii) underlying lung disease; (iii) the RA disease process; (iv) current smoking. (i) Drug therapy in RA: For over half a decade glucocorticoids have been used as immunosuppressive drugs in RA. There is evidence that they increase the risk of serious pulmonary infections up to 4-fold in a dose-dependent manner. The mechanisms behind this greatly increased risk will be discussed further in the presentation. TNF-a inhibitors increase the serious pulmonary infection risk up to 2-fold. If patients need higher dosages of glucocorticoids in addition to treatment with TNF-a inhibitors, their risk of infection is substantial. This combination should be used with caution and if possible avoided in RA patients with additional risk factors for pulmonary infection such as older age, smoking, diabetes and underlying lung disease. The use of rituximab in the context of underlying lung disease and chronic pulmonary infection will be reviewed. The risk benefits of MTX in RA will be discussed in context of known chronic pulmonary disease with the possibility of underlying chronic pulmonary infection. (ii) Underlying lung disease in RA: The most common cause of chronic pulmonary infection in RA is underlying lung disease. The prevalence of underlying lung disease exceeds 50% of the RA population. These underlying lung diseases include chronic obstructive airways disease and interstitial lung disease in RA smokers and bronchiectasis and small airways disease in RA non-smokers. The different pathogens commonly associated with these lung pathologies will be discussed. (iii) RA disease process: RA is associated with citrullination of peptides and the relevance of this to pulmonary infection will be explored further. The concept of NETosis and its potential role in RA disease activity and predisposition to chronic pulmonary infection will be discussed. (iv) Current smoking: Current smoking is a significant risk for acute or chronic pulmonary infection and is particularly relevant to RA as it is a known risk factor for both RA and RA associated interstitial lung disease and an independent risk factor for pulmonary infection. Disclosure statement: D.H. has received funding from Roche, Pfizer and BMS for speaker meetings, advisory boards and educational events.