The Role of EDD (Exercise Capacity, Dyspnea, and Diffusing Capacity of Lungs for Carbon Monoxide) Index in Pulmonary Fibrosis Secondary to Scleroderma

Abstract

<strong>Introduction:</strong> Pulmonary involvement secondary to Systemic Sclerosis (SSc) is the major cause of morbidity and mortality in SSc patients. We designed this study to determine the correlation of important lung function parameters with lung High Resolution CT (HRCT) scan findings. <strong>Materials and Methods:</strong> Thirty–two consecutive diffuse SSc patients with pulmonary fibrosis were enrolled in this cross-sectional study. Patients with pulmonary fibrosis secondary to other causes, previous restrictive lung disease, and history of smoking were excluded. Complete lung function evaluation was performed. The EDD (Exercise capacity, Dyspnea, and Diffusing capacity of lungs for carbon monoxide) index was determined. The Warrick score was calculated based on lung HRCT findings. <strong>Results: </strong>The mean age of the patients was 39.18 years ±9.39 (SD).Seventeen (53%) patients were in EDD stage 1 (score: 0≤score≤3), 9 patients (28%) in stage 2 (3<score ≤6), and 6 patients (19%) in stage 3(6<score≤9). The mean Warrick score was 10.84±6.94 (SD).There was statistically significant correlation between EDD index and Warrick score (r=0.72, P=0.001).Also there was statistically significant strong correlation between EDD stages and Warrick scores (r=0.8, P=0.002). <strong>Conclusion:</strong> The results of this study revealed that EDD may be a valuable representative marker of lung involvement in SSc and in the future, it can be a suitable and safe alternate modality comparing lung HRCT in our clinical practice and close follow-up.