OP0141 Ultrasound diagnostic and predictive value of interstitial lung disease in systemic sclerosis.diagnostic and predictive value of ultrasound in the assessment of interstitial lung disease

Background Interstitial lung disease (ILD) is a common complication of Systemic Sclerosis (SSc) and frequently may be cause of death of patients. High resolution computed tomography (HRCT) is the reference imaging tool for the assessment of ILD; however, its use may be limited for both ionising radiation and costs. In this way, pulmonary ultrasound (US) is revealing interesting potential in the assessment of ILD. Objectives To determine the validity of pulmonary US in detecting subclinical ILD in SSc and to determine its predictive value for detecting disease progression. Methods We included 133 SSc patients≥18 years-old without respiratory symptoms. Individuals with previous diagnosis of ILD or other pulmonary diseases were excluded. A rheumatologist performed the Borg scale dyspnea index, Rodnan skin score (RSS) and lung auscultation to confirm the subclinical respiratory status. Chest X-ray and respiratory function tests (RFT) were performed the same day in all patients. US was performed by a rheumatologist expert who was blinded to clinical assessment. To determine the concurrent validity HRCT was performed. Finally, serologic tests (anti-centromere, anti-Scl70) were obtained. HRCT findings were scored according to Warrick score, whereas US findings were classified according the previously proposed semiquantitative scale (0=normal,≤5 B-lines; 1=slight,≥6 and≤15 B-lines; 2=moderate,≤16 and≥30 B-lines; 3=severe,≥30 B-lines). In order to evaluate the inter-observer reliability, 50% of patients were assessed by 2 rheumatologists with different experience in US; both blinded to clinical data. A healthy control group matched for age and gender was included. A follow-up including US, RFT and Borg scale was done every 3 months until 12 months. Results A total of 54 of 133 patients (40.6%) showed US signs of ILD in contrast to healthy controls (4.8%) (p=0.0001). The clinical and laboratory variables associated with ILD were: anti-centromere antibodies (p=0.005), Borg scale(p=0.004) and RSS(p=0.004). A positive correlation was demonstrated between the US and HRCT findings (p=0.001), confirmed also with the Chi square test (p=0.006). No association was shown with gender, age, disease duration, chest X-ray or RFT. Sensitivity and specificity of US in detecting ILD was 91.2% and 88.6% respectively. A Moderate inter-observer reliability of US findings was observed (kappa 0.50). In follow-up, a total of 30 patients (22.6%) that demonstrated ILD during first evaluation, showed US worsening in their ILD status. Interestingly, 9 of those 30 patients (30%) became symptomatic by the Borg scale. The elapsed time in which progression of ILD or clinical conditions was documented was between 6 and 9 months of follow-up. Conclusions US showed a high prevalence of subclinical ILD in SSc patients. It demonstrated to be a valid, reliable and feasible tool to detect ILD in SSc and to follow-up its evolution. On the basis of our results we believe that US can be implemented as a screening tool for diagnosis of subclinical ILD in SSc. Disclosure of Interest None declared