ILD is a serious manifestation of connective tissue diseases (CTD) often exhausting the definition of progressive pulmonary fibrosis (PPF). Our study aimed to evaluate CTD-ILD cases discussed by the multidisciplinary ILD team (MDT) for functional progression.

Our MDT discussed cases (N=217) between 07/01/2019 and 10/30/2020: CTD-ILD 17.5%, hypersensitivity pneumonitis 9.7%, idiopathic interstitial pneumonias 34.6%, granulomatous ILDs 11.5%, others 26.7%. Baseline pulmonary symptoms, BMI, lung function, were processed in all cases. Out of 38 confirmed CTD-ILD, functional follow-up data were available in 29 cases.

CTD-ILD patients were mainly women (73.7%) and non-smokers (60.5%). Most common symptoms were cough (68.4%), dyspnea (60.5%) and joint pain (60.5%). Lung function test showed a mild restrictive ventilatory disorder and a decrease in diffusion (FVC %: 81.9 ± 23.9, DLCO 73.3 ± 22.6 %). In 10 cases, the adjusted rate of decline in FVC% and DLCO% reached the functional progression defined in the new ATS/ERS guideline. No differences were observed between the functional (f) PPF (Group1, N=10) and stable (Group2, N=19) groups at baseline. During follow-up, Group1 was characterized by a median 17.14% (range: 5.22-19.85%) decline in FVC and 17.82 (range:13.71-39.69%) in DLCO. Weight loss was more prominent in Group1 (?body mass index 2.4 vs. 1.3 kg/m2, p=0.02) compared to Group2.

In CTD-ILD, 26.3% of patients met criteria of functional progression. Weight loss is an important predictor for functional worsening. Regular body weight monitoring and lung allow timely recognition of progression.