Interstitial lung disease in asymptomatic patients at the onset of inflammatory rheumatic diseases

BackgroundInterstitial lung disease (ILD) in inflammatory rheumatic diseases (IRD) is associated with increased mortality. Moreover, the lung is one of the most effected organs on IRD, but the clinical manifestations and severity can vary from subclinical abnormality to dyspnoea, respiratory failure, and death.ObjectivesThe objective of the following study is to evaluate the frequency and type of ILD in asymptomatic patients at the onset of IRD.MethodsThe study represents a sub-analysis of a case-control study performed earlier, and includes 126 patients with a newly diagnosed IRD. The study cohort was divided in two groups (ILD group: n = 63 and control group: n = 63). The patients were evaluated for respiratory symptoms (cough, sputum, dyspnea) and sclerosiphonia. If possible, all patients received a lung function test and optional a chest x-ray. Patients with pathological findings in the screening tests (chest x-ray or reduced diffusing capacity for carbon monoxide (DLCO) < 80 %) maintained a high-resolution computer tomography (HR-CT) of the lung. The sub-analysis includes 20 patients with asymptomatic ILD at the onset of IRD.ResultsThe asymptomatic ILD group consists out of 75 % female (n = 15) and 25 % male (n = 5) patients, with median age of 51.8 years (SD ± 17.1 years). In comparison, asymptomatic ILD patients are significant younger (t(27.4) = 2.36, p = 0.026), but the distribution of gender is similar. The mean values in different pulmonary function parameter are: FVC: 89.9% ± 19.3%; DLCO: 69.9% ± 21.2%; FEV1: 87.9% ± 21.4%; TLC: 91.0% ± 16.5% and TLCO: 82.1% ± 20.6% (FVC = Forced Vital Capacity, FEV1 = Forced Expiratory Volume in 1 second, TLC = Total Lung Capacity, TLCO = Transfer factor of the Lung for carbon monoxide). The observed CT patterns are pure ground glass opacities (GGO) (50%, n = 10), non-specific interstitial pneumonia (NSIP) (25%, n = 5), granuloma/proliferations (15%, n = 3), usual interstitial pneumonia (UIP) (5%, n = 1) and lymphocytic interstitial pneumonia (LIP) (5%, n = 1). The distribution of CT pattern was not significant to the symptomatic ILD group (χ2(6) = 10.224, p = 0.116).ConclusionThe study highlighted that also clinical asymptomatic patients have ILD in IRD at the onset of the IRD. Frequently, a reduced DLCO is detectable in PFT as a sign of early lung involvement, so this represents a potential screening parameter. Moreover, asymptomatic patients are often younger than symptomatic patients. No significant difference was found in CT pattern, but further research is needed as the number of patients is quite small.Disclosure of InterestsNone declared