Pepsin in saliva for the diagnosis of gastro-oesophageal reflux disease

Objective Current diagnostic methods for gastro-oesophageal reflux disease (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 healthy asymptomatic subjects and to determine its value to discriminate patients with reflux-related symptoms (GORD, hypersensitive oesophagus (HO)) from functional heartburn (FH). Design 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); HO (normal AET and + Symptom Association Probability (SAP), n=26) and FH (normal AET and-SAP, n=27). Results 1/3 of asymptomatic subjects had pepsin in saliva at low concentration (0(0-59) ng/mL). Patients with GORD and HO had higher prevalence 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 and concentration of pepsin in saliva (0(0-40) ng/mL). A positive test had 78.6% sensitivity and 64.9% specificity for diagnosis of GORD + HO (likelihood ratio: 2.23). However, one positive sample with >210 ng/mL pepsin suggested presence of GORD+ HO with 98.2% specificity (likelihood ratio: 25.1). Only 18/84 (21.4%) of GORD+ HO patients had 3 negative samples. Conclusion In patients with symptoms suggestive of GORD, salivary pepsin testing may complement questionnaires to assist office-based diagnosis. This may lessen the use of unnecessary antireflux therapy and the need for further invasive and expensive diagnostic methods.