Pilot study evaluating salivary bile acids as a diagnostic biomarker of laryngopharyngeal reflux

Bile acids in refluxate contribute to esophageal and laryngeal symptoms and are quantifiable. The aim of this study was to compare salivary bile acid concentrations across healthy controls and symptomatic patients (esophageal or laryngeal) with or without objective gastroesophageal reflux disease (GERD). This prospective study enrolled adults into three groups: esophageal symptoms (heartburn, regurgitation, chest pain); laryngeal symptoms (cough, throat clearing, sore throat, dysphonia); and controls. Symptomatic patients primarily underwent prolonged wireless reflux monitoring off acid suppression and were categorized as symptomatic no GERD (acid exposure time <4%) or esophageal/laryngeal symptoms with GERD (acid exposure time ≥4%). Controls did not undergo reflux monitoring nor upper endoscopy. Saliva samples were provided for bile acid analysis via ultraperformance liquid chromatography tandem mass spectrometry. Thirty-five participants were enrolled (mean age 47.4 years [SD 18.9], 16 [46%] male), including 10 controls and 25 symptomatic: 9 no GERD, 5 esophageal symptoms + GERD, and 11 laryngeal symptoms + GERD. Total salivary bile acids were highest in the laryngeal symptoms + GERD group (24.2 nM [SD 24.7]) compared to other groups (controls: 5.8 [6.0], P = 0.03; symptomatic no GERD: 3.1 [4.4]; P < 0.01; esophageal symptoms + GERD: 7.1 [7.1], P = 0.10). Bile acids were elevated in 45% (5/11) of the laryngeal symptoms + GERD group compared to 0% of the other three groups (P < 0.01). Salivary bile acids were higher among patients with laryngeal symptoms and objective GERD versus other groups. Salivary bile acids are a quantifiable biomarker with diagnostic potential for laryngopharyngeal reflux.