Abstract
Objectives: Treatment of connective tissue disease related
interstitial lung disease (CTD-ILD) remains challenging. The literature
related to the immunosuppressive drugs is very limited in most CTDs and
there is no previously reported study comparing induction regimens in
patients with newly defined ‘interstitial pneumonia with autoimmune
features (IPAF), We aimed to investigate the efficacy of azathioprine
(AZA) used in induction regimens for interstitial lung disease in a
variety of connective tissue disorders including IPAF, and compare it
with cyclophosphamide (CYC)
Methods. In a retrospective study, all patients presented with
interstitial lung disease to the rheumatology and/or pulmonology
departments in a tertiary referral center, between 2009 and 2019. Five
major CTD groups were defined; systemic sclerosis, rheumatoid arthritis
(RA), primary Sjögren syndrome (pSS), inflammatory myositis (IMS) and
interstitial pneumonia with autoimmune features (IPAF). All patients who
satisfied one of these and received AZA or CYC for induction therapy for
at least 6 months were included in the study. Treatment responses at six
months and side effects were analyzed.
Results : There were 1351 patients diagnosed with ILD. Of
these,, 328 patients were identified as CTD-ILD, satisfying
classification criteria of one of the CTDs. Among these, 57 patients
received AZA and 79 patients received CYC for induction therapy. CYC
treatment resulted in 2.41 % increase in FVC, however AZA resulted in
1.44% decline in FVC predicted (p=0.041). Propensity score matching was
used to reduce selection bias, AZA treatment was related to increased
risk of progression (50% vs 13.5%, p:0.002) .
Conclusion: CYC is superior to AZA in induction therapy of
CTD-ILD.
Key words: Azathioprine, Connective tissue disease,
Cyclophosphamide, Interstitial lung disease, , interstitial pneumonia
with autoimmune features, treatment