Utility of the expiratory disproportion index in early detection of idiopathic subglottic stenosis masked by asthma.
Idiopathic subglottic stenosis (iSGS) is a rare fibrotic condition causing fixed extrathoracic airway obstruction, predominantly affecting postmenopausal women. The expiratory disproportion index (EDI), calculated as forced expiratory volume in one second (FEV1) (mL)/peak expiratory flow (PEF) (L/min), can help differe...