Consistency between oscillometry and spirometry in patients with asthma or COPD

Background: Spirometry, the gold standard for assessing airflow limitation, requires full forceful breathing and operator/interpreter training, and may be time-consuming/challenging in patients (pts) with impaired capacity to cooperate. Many thus fail to obtain accurate diagnoses and appropriate treatment. Aims: This study assessed the consistency between oscillometry and spirometry in pts with suspected or confirmed asthma or COPD. Methods: Eligible pts from 46 hospitals in China underwent oscillometry using the Ambulatory Lung Diagnosis System (ALDS), followed by spirometry. Primary endpoint was consistency between oscillometry and spirometry (normal/abnormal) pre-bronchodilator test (BDT), evaluated by Cohen’s Kappa coefficient (κ). Results: Of 801 enrolled pts, 788 completed pre-BDT tests; results showed moderate agreement between tests (κ=0.4188, 95% CI 0.3556–0.4820, Table 1). Post-BDT results in the COPD group also showed moderate agreement (κ=0.4662, 95% CI 0.3803–0.5521); however, the positive and negative predictive values, sensitivity and specificity of ALDS for detecting pts with a spirometry-confirmed COPD diagnosis were 87.4%, 58.7%, 69.6% and 81.2%, respectively (Table 2). erj;66/suppl_69/PA2520/F1F1F1 Conclusions: Oscillometry showed only moderate consistency with spirometry, but the high positive predictive value in COPD group suggests its potential as an alternative rule in diagnostic test for COPD in pts or settings where spirometry is not feasible.