Is early diagnosis of COPD possible? Preliminary results of early COPD study

COPD diagnosis is based on spirometric detection of irreversible airway obstruction. However, the wide pulmonary functional reserve may make spirometry insensitive. Aim of the study is to assess whether second-level pulmonary functional tests and exercise testing allow an early diagnosis of COPD. 3 groups of subjects were enrolled: 1) EARLY: high pre-test probability of COPD (smoking history ≥ 10 py and exertional dyspnea not related to heart disease, and FEV1/FVC between the 5th and the 20th percentile of predicted values); 2) mild-to-moderate COPD; 3) HEALTHY (asymptomatic, smoking history ≤ 10 py, normal spirometry). All patients underwent a detailed anamnestic assessment, global spirometry, DLCO, single breath nitrogen wash-out (SBN 2 ), forced oscillation technique (FOT), six-minutes walking test (6MWT, with continuous flow and volumes evaluation) and cardiopulmonary exercise test (CPET). 19 patients were recruited: 6 EARLY, 7 HEALTHY and 6 COPD patients. Between EARLY and HEALTHY subjects, no significant difference in terms of dynamic hyperinflation and ventilatory reserve at 6MWT and CPET. However, we found a significant difference between groups in terms of SBN 2 slope (p ‹ 0.001). FOT, thoracic gas volume and FEF 25-75% values were different, although not statistically significant. Our preliminary results show a sensitivity gap in the exertional pulmonary functional tests for early diagnosis of COPD. The SBN 2 slope could early identify small airway obstruction.