Saliva testing for the diagnosis of reflux disease in infants

Rationale: GERD is common in infants with a prevalence of >12% in the western population. To prevent over- as well as under diagnosis and treatment of infant GERD, there is a clear need to distinguish mild GER related symptoms from pathological GERD in this large group of patients. Currently, the international guidelines propose combined pH and multichannel intraluminal impedance (pH-MII) as a diagnostic tool to assess GERD. However, normal values are lacking and it is unclear how the results of this test relate to treatment outcome. Salivary pepsin measurement has been shown a specific marker for GERD in adults and is a simple, non invasive test. The additional diagnostic and predictive value of pepsin measurement in saliva of symptomatic infants is unknown.

Objective: To test the hypothesis that salivary pepsin tests can play a role in the diagnostic process of infant GERD:

- by excluding GERD; and/or

- by establishing GERD in an early stage of the disease and/or establish the need for further invasive testing

Study design:

1. Cross sectional study in healthy control infants

2. Prospective outcome study in infants with GERD

Study population:

Healthy infants and infatns with GERD from the United Kingdom and The Netherlands

Study protocol: Saliva samples from healthy controls once. Saliva samples from symptomatic infants will be collected at standardized timepoints during a standardized diagnostic and treatment protocol.

Main study parameters/endpoints:

In healthy controls, salivary pepsin A concentrations will be determined to create a reference range
In symptomatic infants, baseline salivary pepsin A concentrations will be compared to healthy controls and correlated with clinical outcome during standardized treatment.

Salivary pepsin tests can play a role in the diagnostic process of infant GERD:

- by excluding GERD; and/or

- by establishing GERD in an early stage of the disease and/or establish the need for further invasive testing

1.Healthy controls:

- IGERQ-R questionnaire at baseline. Score < 16 to qualify as a healthy control.

- Saliva samples will be collected one hour after a feed on two consecutive days using a blunt sterile plastic single use transfer pipette. Samples will be stored in refrigerator and analyzed for pepin <7 days of collection with an pepsin A specific enzymatic assay.

Symptomatic infants:

- IGERQ-R questionnaire at baseline: Score >15 to qualify as a symptomatic infant. Furthermore I-GERQ-R at day 0, day 14 and day 44. At these timepoints response is defined as follows:

* No response: I-GERQ-R above symptomatic score (>15 points) and no significant improvement (improvement in score <5 points) compared to baseline.

* Partial response: I-GERQ-R above symptomatic score (>15 points) but with significant improvement (improvement in score >4 points) in symptom score compared to baseline OR I-GERQ-R below symptomatic score (<16 points) but no significant improvement (improvement in score >4 points) in symptom score compared to baseline.

* complete response: I-GERQ-R drops below symptomatic score (<16) AND a significant improvement of score (improvement in score >4 points)



- Saliva samples will be collected one hour after a feed at presentation and after two weeks of standard conservative treatment. If the infants have no response or a partial response to this conservative therapy, saliva samples will again be collected at the end of an additional 4 weeks trial of proton pump inhibitor (PPI) treatment. Salivary pepsin will be determined using the method described above.

- 24 hour pH-multichannel intraluminal impedance (pH-MII) will be performed when infants have no response or a partial response to 2 weeks of standard conservative treatment. Reflux index(RI), symptom index (SI), symptom sensitivity index (SSI) and symptom association probability score (SAP) will be used to determine a positive or negative result.

2 weeks of 1 daily 1 mg/kg omeprazol therapy in symptomatic children not responding to 2 weeks of conservative treatment.