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Physiology‐based minimum clinically important difference thresholds in adult laryngotracheal stenosis
Author(s) -
Nouraei S. Mahmoud,
Franco Ramon A.,
Dowdall Jayme R.,
Nouraei S. A. Reza,
Mills Heide,
Virk Jag S.,
Sandhu Guri S.,
Polkey Mike
Publication year - 2014
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1002/lary.24641
Subject(s) - medicine , minimal clinically important difference , laryngotracheal stenosis , vital capacity , stenosis , airway , prospective cohort study , cardiology , surgery , randomized controlled trial , tracheal stenosis , lung , diffusing capacity , lung function
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) (ΔAUC Total /FVC), and treatment‐related changes in the MRC grade (ΔMRC) ( r = −0.76 and r = −0.82, respectively). Both TPF and AUC Total /FVC discriminated between effective (ΔMRC <0) and ineffective (ΔMRC ≥0) interventions, yielding MCID values of 4.2 L/s for TPF and 2.1 L 2 /s for AUC Total /FVC, respectively. Ten patients required airway treatment for recurrent disease, and TPF and AUC Total /FVC levels had distribution‐based MCID values of 0.9 and 0.6, respectively. Conclusions Flow‐volume loops provide a quantitative method of objectively assessing outcomes in LTS. TPF is the most convenient index for this purpose, but AUC Total /FVC provides marginally greater sensitivity and specificity. Level of Evidence 4 Laryngoscope 124:2313–2320, 2014