(0219) Evaluating the Credibility of Minimal Clinically Important Differences for Patient-Reported Outcome Measurements in Otolaryngology

Introduction: The minimal clinically important difference (MCID) of a patient reported outcome (PROM) is essential to identify a significant change in patients’ perceived health status. Although anchor-based methods are widely used for determining MCIDs, differences in anchor choice and statistical approach can lead to variability in their reliability. Despite the widespread use of PROMs in otolaryngology, no prior research has rigorously examined the methodologies behind establishing anchor-based MCIDs in our field.

Methods: We identified studies that determined an MCID for outcomes measures from a previously published systemic search of the otolaryngology literature conducted from inception of the databases to November 2, 2021. We then applied a validated instrument to evaluate the credibility of the anchor-based MCIDs of the PROMs from these studies.

Results: A total of 25 studies described anchor-based MCIDs for 22 unique PROMs across a range of subspecialties, most commonly rhinology (n = 7) and otology (n = 6). A total of 43 MCIDs were reported across all PROMs and their sub-domains using 68 different anchors. Of the MCID-anchor combinations, 35% (n = 24/68) were determined to have acceptable credibility. In 66% (n = 45/68), the anchors used were clinically relevant to patients and easy to understand. Correlations between the PROM and the anchor were not reported in 16 of 68 cases (24%). Among the 52 studies which did report this correlation, 90% (n = 47/52) were considered credible with a threshold of R > 0.3. In 15% of all cases, the selected change in anchor score failed to meet the criteria of both “small and clinically important.” When global rating of change anchors were used (n = 25), the time interval at follow-up was considered prolonged (> 3 months), introducing opportunities for recall bias.

Conclusions: Our findings suggest that a minority of MCIDs display credibility based on the criteria of the instrument in otolaryngology studies and highlight the need for standardized guidelines to validate that reported MCIDs are accurate and reliable.