Association between Reflux Symptom Index scores and modified Mallampati class in adults undergoing upper gastrointestinal endoscopy: a prospective cross-sectional study

Abstract Background The modified Mallampati classification is a routine component of preoperative airway assessment. We examined whether throat-predominant symptom burden, measured with the Reflux Symptom Index (RSI), and typical esophageal symptom burden, measured with the Gastroesophageal Reflux Disease Questionnaire (GerdQ), are associated with modified Mallampati class in adults undergoing elective upper gastrointestinal endoscopy. Methods In this prospective cross-sectional exploratory study, 90 adults with reflux-type symptoms of more than one year’s duration were enrolled. Participants using proton pump inhibitors were instructed to stop treatment for at least 14 days beforehand. Modified Mallampati class was graded from standardized photographs by a blinded assessor. The primary outcome was Mallampati class III–IV and the primary exposure was continuous RSI score. The main adjusted model included RSI, body mass index (BMI), neck circumference and current smoking, with Firth penalized logistic regression as a robustness analysis. Secondary analyses examined the four Mallampati categories. Results Thirty-five participants (38.9%) had Mallampati class III–IV. RSI scores were higher in the III–IV group than in the I–II group (13.97 ± 7.14 vs 8.27 ± 6.67; p < 0.001). In the main adjusted model each 1-point increase in RSI was associated with Mallampati III–IV (OR 1.13, 95% CI 1.04–1.22; p = 0.002; OR 1.84, 95% CI 1.24–2.73 per 5 points). Firth penalization and restriction to participants who were not current smokers (OR 1.26, 95% CI 1.04–1.52) gave a concordant direction of association. RSI did not rise monotonically across the four categories and the proportional-odds assumption was violated (p = 0.0015). GerdQ scores did not differ between groups (p = 0.65). Conclusions Higher RSI-defined throat symptom burden was associated with modified Mallampati class III–IV, and the association persisted after adjustment and in sensitivity analyses. No evidence of an association between GerdQ score and Mallampati class was observed. Because the relationship was not graded across all four categories and no objective reflux testing was performed, these exploratory findings describe a relationship between upper-airway symptom burden and oropharyngeal phenotype rather than evidence of reflux disease.