PWE-172 Does salivary pepsin measurement change diagnostic outcome in patients investigated by 24h ph monitoring?

Abstract

Introduction Pepsin, a gastric enzyme, has been proposed as a marker of gastro-oesophageal reflux disease (GORD) when present in saliva.1 In contrast to routine diagnostic methods, quantification of salivary pepsin is rapid and non-invasive. Furthermore, 24h pH-monitoring has limited sensitivity.2We aimed to evaluate the impact of salivary pepsin measurement on diagnosis of GORD in patients undergoing 24h pH-monitoring. Method Patients referred for 24h pH-monitoring (off medication) were invited to take part in the study. Eligible participants complained of heartburn, regurgitation, chest pain or acid in the mouth and were referred for testing by a gastroenterologist, upper gastrointestinal surgeon or respiratory consultant. Presence of additional atypical symptoms was assessed by questionnaire (Reflux Symptom Index). Patients underwent high resolution oesophageal manometry and catheter-based 24h pH-monitoring. During the monitoring period, participants collected up to three saliva samples at the time of experiencing their predominant symptom (s). Pepsin concentration of samples was quantified using a lateral flow device (Peptest) where at least one sample containing >25ng/ml pepsin was indicative of reflux disease. Diagnostic outcome by pepsin measurement and 24h pH-monitoring (>4.2% of time pH Results 100 participants recruited; 80 participants included in final analysis (exclusions: corrupt pH study (n = 1), no pepsin samples collected (n = 19)). 81% of participants returned at least one positive pepsin sample. 39/80 (49%) patients were classified as having reflux disease based on 24h-pH monitoring (mean%time pH Conclusion A higher proportion of the total population was found to have GORD based on pepsin measurement (81% vs 49% using pH), which may reflect the poor sensitivity of 24h pH-monitoring. Measurement of salivary pepsin changed the diagnostic outcome when compared to 24h pH-monitoring in 44% of symptomatic reflux patients. Further studies should explore the relationships between pepsin concentration and symptoms of reflux. This study may support the use of salivary pepsin measurement to prevent false-negative diagnosis based on 24h pH-monitoring alone. Disclosure of interest A. Rasijeff: None Declared, W. Jackson: None Declared, J. Burke: None Declared, P. Dettmar Shareholder of: RD Biomed Limited. References Hayat JO, et al. Gut 2015;64:373–380 Dent J, et al. Gut 2010;59:714–721