The minimal clinically important difference of the dyspnea index in laryngotracheal stenosis

The minimal clinically important difference of the dyspnea index in laryngotracheal stenosis:

Objective

The Dyspnea Index (DI) is a validated patient‐reported outcome (PRO) instrument that has been used in the management of laryngotracheal stenosis (LTS). The minimal clinically important difference (MCID) is an established concept to help determine the change in a PRO instrument that reflects meaningful change for the patient. It is not known what change in the DI is of clinical significance in airway surgery. This study aims to determine the MCID for the DI in patients undergoing surgical treatment for LTS.

Methods

This is a prospective cohort study in which 26 patients with LTS completed the DI (score range 0 to 40) before and 6 to 8 weeks postoperatively, in addition to a Global Ratings Change Questionnaire (GRCQ), scored from −7 to +7, at the postoperative interval. A hypothesis test was carried out to test the association between GRCQ and change in DI. The MCID for change in DI was determined using anchor‐based analysis.

Results

Overall mean change in DI was −11, and mean change in GRCQ was +5. Change in DI scores were significantly different among the improvement and no improvement groups (P value <0.002). Area under the receiver operating curve was 0.92, demonstrating high discriminatory ability of the change in DI score. A change of −4 was determined to be the threshold that discriminated between significant improvement and no improvement.

Conclusion

A decrease of 4 in the DI can be considered as the MCID for patients with LTS after surgical treatment.

Level of Evidence

2b Laryngoscope, 2019