Introduction Current diagnostic tests for GORD have moderate sensitivity/specificity and can be invasive and expensive. Pepsin detection in saliva has been proposed as an “office-based” method for GORD diagnosis. The aims of this study were to establish normal values of salivary pepsin in a large cohort of healthy asymptomatic subjects and to determine its value to discriminate patients with reflux-related symptoms (GORD, hypersensitive oesophagus) from functional heartburn.

Methods 100 asymptomatic controls and 111 patients with heartburn underwent MII-pH monitoring and simultaneous salivary pepsin determination on waking, after lunch and dinner. Cut off value for pepsin positivity was 16 ng/ml. Patients were divided into GORD (increased acid exposure time (AET) n = 58); Hypersensitive Oesophagus (HO) (normal AET and + SAP), n = 26) and Functional Heartburn (FH) (normal AET and – SAP, n = 27). Multiple group comparisons were performed using one-way ANOVA followed by with Tukey’s Test for Gaussian distributed data and the Kruskall-Wallis Test with Dunns comparison for non-Gaussian data. Receiver Operator Characteristic curves were constructed to determine and compare the sensitivity and specificity of different pepsin cut-off concentrations.

Results 1/3 of asymptomatic subjects had pepsin in saliva at low concentration (0(0–59) ng/ml). Patients with reflux-related symptoms (GORD and HO) had higher prevalence (77–89%) and pepsin concentration than controls (HO, 237(52–311) ng/ml and GORD, 121(29–252) ng/ml) (p < 0.05). Patients with FH had low prevalence (33%) and concentration of pepsin in saliva (0(0–40) ng/ml). The area under the receiver operating characteristic curve had a value of 0.8034 +/-0.04 (95% confidence interval 0.719 to 0.8873, p < 0.0001). A positive test had 77.6% sensitivity and 63.2% specificity for diagnosis of GORD/HO. When all saliva samples were negative, there was 80% probability that symptoms were not due to reflux (FH). One positive sample with >210 ng/ml pepsin suggested the presence of GORD/HO with 95% probability.

Conclusion In patients with symptoms suggestive of GORD, salivary pepsin can be used to confirm or reject the diagnosis before empirical PPI treatment. This may lessen the use of unnecessary anti-reflux therapy and the need for further invasive and expensive diagnostic methods.

Disclosure of Interest J. Hayat: None Declared, S. Gabieta-Somnez: None Declared, E. Yazaki: None Declared, J.-Y. Kang: None Declared, A. Woodcock Employee of: RD Biomed Ltd, P. Dettmar Employee of: RD Biomed Ltd, J. Mabary Employee of: Sandhill Sci., C. Knowles: None Declared, D. Sifrim Grant/research support from: Sandhill Sci.