We read the article of Guo and Xie entitled, "Gastroesophageal Reflux and Chronic Rhinosinusitis: A Mendelian Randomization Study." 1 Authors conducted a two-sample Mendelian randomization analysis to explore the association between gastroesophageal reflux disease (GERD) and chronic rhinosinusitis (CRS). They mainly used genome-wide association studies, which include data for several thousand asymptomatic individuals and patients with CRS, to explore the association with GERD. GERD was identified through the consumption of omeprazole, the international classification of disease, and self-reported GERD symptoms. 1 We congratulate the authors for this article, which investigated a complicated topic. However, we would like to draw attention to some methodological points.The criteria used for the GERD diagnosis do not corroborate those of the Lyon consensus article, which consist of peptic esophageal stricture, grade C/D esophagitis, or acid exposure time >6% at the pH monitoring. 2 Many healthy individuals reported GERD symptom without having GERD, 3 which makes biased the only consideration of GERD symptoms for the GERD diagnosis confirmation. The potential association between reflux and respiratory disorders (e.g., CRS and asthma) needs to carefully consider the back-flow of gastroduodenal content into the respiratory mucosa, which includes pepsin, bile salts, or other enzymes. [4][5][6] The presence of reflux events (hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring [HEMII-pH]), enzymes, symptoms, and findings may suggest the presence of laryngopharyngeal reflux (LPR). 7 LPR is unrelated to GERD, and GERD does not involve LPR. 7 Indeed, twothirds of GERD patients do not report LPR, 3 whereas patients with >1 event at the HEMII-pH (LPR diagnosis) do not have GERD according to the Lyon consensus. 2,7 Most reflux events in the distal esophagus do not reach the