Background Interstitial lung disease (ILD) is associated with Rheumatoid arthritis (RA) in 3.7% - 7.7% of patients. Methotrexate induced pneumonitis is a rare and unpredictable toxicity leading to withdrawal of treatment in 1:108 patient years. British Society of Rheumatology (BSR) guidelines for pre- methotrexate treatment screening include chest x-ray and in certain cases pulmonary function tests and high resolution CT scan (HRCT). It is also recommended that methotrexate is best avoided in established cases of interstitial lung disease.
Objectives The aim of our audit was to check compliance with BSR guidelines.
Methods We have conducted a retrospective audit on 40 RA patients treated with methotrexate with preferential selection of patients with lung disease. We looked at their records to obtain details of screening chest investigations and also any subsequent chest investigations carried out and the reasons prompting the investigations and the actions taken.
Results Our cohort included patients with the median age of 63 years (Range 25 -87). There was an equal gender distribution. 80% of the patients were seropositive. Patients had pre-existing lung disease in 20% of which 50% had COPD, 25% Fibrosis, 25% benign pathology. A screening chest X-ray was performed in 97.5% of the patients with 31% being reported as abnormal. Fifty eight percent of the patients with abnormal chest x ray were symptomatic with shortness of breath (SOB) (86%) followed by cough. All these patients had subsequent HRCT revealing ILD in 57%, combination of emphysema and fibrosis in 29% and pneumonitis in 14%. All these patients were subsequently referred to a respiratory physician and methotrexate was withdrawn.
Fifty five percent of the patients with normal chest x-ray at screening subsequently developed chest symptoms (SOB (53%) and cough (34%)). Sixty seven percent of these patients had abnormal chest x rays. HRCT was requested in 80% of these patients revealing ILD in 47%. One symptomatic patient was found to have lung cancer. All of the ILD patients were subsequently referred to a respiratory physician and methotrexate was withdrawn.
The duration of methotrexate to onset of symptoms and withdrawal varied from 14 months to 12 years.
Conclusions Appropriate pre-treatment screening for lung disease was performed in all patients commencing methotrexate. All patients with established ILD had methotrexate withdrawn. There is evidence for continuing methotrexate in RA patients who develop ILD with careful monitoring. However currently there are no guidelines concerning continuation or withdrawal of methotrexate in patients who develop ILD during the course of treatment.
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Disclosure of Interest None declared
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