Minimal clinically important differences on the DyNaChron questionnaire after surgery

Objectives: To determine minimal clinically important differences (MCIDs) for the DyNaChron chronic rhinosinusitis quality-of-life questionnaire.

Introduction: MCIDs are the smallest changes in a quality-of-life score that are of clinical relevance for the patient. They allow treatment benefit to be estimated. MCIDs have not previously been determined for DyNaChron.

Material and methods: A single-center retrospective study analyzed DyNaChron questionnaires filled out between June 2016 and December 2021 by all patients consulting for chronic nasal dysfunction. Five hundred and thirteen of the 2390 patients were operated on for nasal polyposis (NP; n=282) or septo(rhino)plasty+inferior turbinoplasty (SPIT; n=231). Standard error of measurement was used to determine MCIDs.

Results: MCID for DyNaChron global score was 60 in NP and 58 in SPIT. MCIDs per symptom domain in NP and SPIT respectively were: 15 and 13 for nasal obstruction, 21 and 21 for anterior rhinorrhea, 20 and 19 for posterior rhinorrhea, and 17 and 17 for olfaction. In agreement with global MCID, 257 NPs (91%) and 149 SPITs (65%) showed clinical improvement.

Conclusion: MCID helps assess response to treatment. In the DyNaChron questionnaire, MCIDs enable global and symptom-specific assessment of chronic nasal dysfunction and its impact on quality of life in a single patient or in groups.