Physiology-based minimum clinically important difference thresholds in adult laryngotracheal stenosis

Objectives/Hypothesis Delivering evidence‐based patient care is predicated on the availability of objective and validated outcome measures. We aimed to calculate physiology‐based minimum clinically important difference (MCID) values for adult laryngotracheal stenosis (LTS). Study Design Prospective observational study. Methods Patient demographics, morbidities, and stenosis severity were assessed preoperatively. Flow‐volume loops and Medical Research Council (MRC) dyspnea grades were measured in 21 males and 44 females before and 6 to 8 weeks after airway surgery, and before treating recurrent disease in 10 patients. Anchor and distribution‐based methodologies were used to calculate MCIDs for treatment efficacy and disease recurrence respectively. Results The mean age at treatment was 46 ± 16 years. The most common etiology was idiopathic subglottic stenosis (38%). Most lesions (66%) obstructed >70% of the lumen. There were strong correlations between treatment‐related changes in total peak flow (TPF) (ΔTPF) (peak expiratory flow + |peak inspiratory flow|) and the ratio of area under the flow‐volume loop (AUC) to forced vital capacity (FVC) (ΔAUCTotal/FVC), and treatment‐related changes in the MRC grade (ΔMRC) (r = −0.76 and r = −0.82, respectively). Both TPF and AUCTotal/FVC discriminated between effective (ΔMRC