Experience of connective tissue related interstitial lung disease in combined respiratory and rheumatology clinic.

<bold>Background:</bold> CTD related ILD is a heterogenous disease. Regardless of the underlying cause, a percentage of patients have a progressive course warranting anti-fibrotic drugs and lung transplant assessment. <bold>Objective:</bold> The aim of this study was to describe CTD related ILD cases with progressive pulmonary fibrosis (PPF) using PPF guidelines. <bold>Methods:</bold> Data from October 2022 to December 2023 was collated including patient demographics, CT thorax, pulmonary function test at baseline and over 12 months and the current treatment. <bold>Results:</bold> A total of 89 patient were included. 73.04 % (n=65) were female. 41.5% (n=44) were never smokers. The commonest diagnosis was RA- ILD 33.71% (n=30), followed by myositis related ILD 14.61% (n=13). Predominant inflammatory CT findings were observed in 60.67% (n=54) and predominant fibrotic CT findings were observed in 39.3% (n=35). A total of 67 cases met PPF criteria. 53.73 % (n=36) of PPF had predominant inflammatory CT. 13.48% (n=12) of PPF cases received combination therapy (Anti-fibrotic and immunosuppressant). 51.58% (n= 46) on immunosuppressant alone and 10.11% (n=9) not on current treatment. In relation to the total cohort, 20.2% (n=18) needed oxygen therapy, 14.6% (n=13) were on anti-fibrotic, 4.49% (n=4) were referred for lung transplant assessment, 8.98% (n=8) had pulmonary hypertension and 8.98% (n=8) died during follow up. <bold>Conclusion:</bold> Clinical practical guidelines remain essential for defining such heterogenous and complex phenotypes especially for those meeting PPF criteria. Guidance is necessary to establish the timely addition of an anti-fibrotic due to paucity of evidence.