Background:Interstitial lung disease (ILD) is associated with decreased quality of life and higher mortality risk in patients with connective tissue disease (CTD). Outcome and treatment response to immunosuppressive therapies is unpredictable, and therefore the management of CTD-ILD can be challenging.Objectives:Our study aimed to identify clinical and imaging factors that are predictive for outcome in patients with CTD-ILD.Methods:We performed a retrospective cohort study in patients with CTD-ILD who were treated in our centre between 2004 and 2018. Clinical, biochemical data as well as pulmonary function test (PFT) and high-resolution computed tomography (HRCT) results were recorded. Two experienced chest radiologists independently and blindly reviewed the HRCT’s. When the two chest radiologists assessed the ILD pattern differently, a diagnosis was made by consultation of a third expert. The ILD patterns were classified as fibrotic or inflammatory. Overall survival and progressive fibrosing interstitial lung disease (PF-ILD, defined as a significant decline of PFT and HRCT) after two years of treatment were assessed using a Kaplan-Meier plot. Multivariable Cox regression was including for treatment, comorbidity, and age as variables. Factors with a p value < 0.2 in the univariate analysis were included in the multivariate analysis. The correlation between the variation of serum markers and PFT over-time was evaluated with Spearman’s Rho.Results:In total, 150 patients with CTD-ILD were included, of which 53 (35.3%) had systemic sclerosis, 19 (12.7%) Sjogren’s syndrome, 29 (19.3%) inflammatory myopathy, 24 (16%) rheumatoid arthritis, 5 (3.3%) systemic lupus erythematosus, 4 (2.7%) mixed connective tissue disease, and 16 (10.7%) undifferentiated connective tissue disease patients. Median disease duration of CTD was 14 months (IQR 2–73) in patients with CTD diagnosis before ILD onset. The median follow-up duration was 40 months (IQR 27.3–60.8). Thirty (20%) deaths occurred, in which the cause of death was a pulmonary infection in 6 (4%) patients and a respiratory failure due to ILD in 10 (6.7%) patients. PF-ILD occurred in 82 (54.7%) patients, which was associated with poor overall survival (HR 3.03, 95%CI 1.15–7.98) (Figure 1). Age, smoking, and steroid usage were associated with increased mortality risk as well (Table 1). There was no dose-related effect of smoking on mortality.Figure 1.The Kaplan-Meier plot for progressive fibrosing interstitial lung diseases (PF-ILD). PF-ILF was defined as pulmonary function decline or high-resolution computed tomography progression after two years of treatment.Inflammatory patterns on baseline HRCT were correlated with a lower risk of FVC decline than fibrotic patterns (OR 0.24, 95%CI 0.09–0.64). The increase in CA15.3 level was associated with the decline in FVC (Rho -0.308, p=0.037). Besides, the elevation in CRP was associated with the reduction in FVC (Rho -0.302, p=0.006) and DLCO (Rho -0.268, p=0.019).Conclusion:Our study identified several factors associated with outcomes. Age, smoking, and steroid treatment increased the risk of mortality in patient with CTD-ILD. Inflammatory HRCT pattern at baseline revealed a better pulmonary outcome than a fibrotic pattern. The patients having PF-ILD after two years of treatment showed a higher mortality risk.Table 1.Multivariable Cox-regression for the clinical risk of mortality.Clinical factorCrude HR (95%CI)PAdjusted HR (95%CI)pAge1.11 (1.06–1.15)1.7*10-61.12 (1.07–1.17)3.54*10-6Smoking1.64 (0.79–3.43)0.1872.53 (1.11–5.78)0.028Congestive heart failure1.86 (0.75–4.58)0.1791.17 (0.47–2.91)0.737MMF0.55 (0.23–1.35)0.1950.73 (0.29–1.85)0.512Steroid4.37 (1.67–11.45)0.0034.96 (1.84–13.40)0.002MMF, mycophenolate mofetil; HR, hazard ratio.Acknowledgements:We want to thank Marieke Vianen for the support in data management, Lieke Wintermans and Lisa Hessels for collecting the clinical data.Disclosure of Interests:None declared
Predictors of Mortality in Progressive Fibrosing Interstitial Lung Diseases
