Do sociodemographic factors influence the MCID of the orofacial esthetic scale?

Background

Orofacial esthetics, reflecting the appearance of teeth, mouth, and face, is a key dimension of oral health-related quality of life (OHRQoL). The Orofacial Esthetic Scale (OES) is a validated patient-reported outcome measure. However, its minimal clinically important difference (MCID) remains insufficiently understood. In particular, it is unclear whether MCID estimates vary across sociodemographic groups. Therefore, this study aimed to explore potential differences according to gender and language.

Methods

In this prospective study, 2,115 adults were recruited in Minnesota, USA, between July 2014 and April 2016. Follow-up data were available for 539 participants (median age: 58 years; 61% female), of whom 503 were included in the analysis. The OES was completed in Spanish or English at baseline and after six months. The OES consists of eight items, with the first seven summed to a score from 0 to 70. Perceived changes were assessed using a 7-point Likert anchor question (“very much improved” to “very much worse”). The MCID was defined as the median change among participants reporting “minimal improvement”, with 95% confidence intervals (CI). Subgroup analyses were conducted by gender and questionnaire language.

Results

Among all participants with “minimal improvement” (n = 68), the median change in the OES sum score was 1 point (95% CI: −1 to 5), defined as the MCID. Subgroup analyses suggested variability in MCID estimates across gender and language groups, although estimates were imprecise due to limited subgroup sizes. Internal consistency was excellent (Cronbach’s α = 0.95).

Conclusions

The study provides the first anchor-based MCID estimate for the OES and suggests that sociodemographic factors such as gender and language may influence its magnitude. However, the wide confidence intervals and subgroup variability indicate limited precision. Further research is needed to confirm these findings and to establish robust, group-specific MCID thresholds.

Key messages

• The MCID of the OES may vary across sociodemographic groups, highlighting the importance of subgroup-specific interpretation.

• While the OES demonstrated excellent reliability, MCID estimates showed considerable uncertainty and require further validation.