Physiological Predictors of Clinical Outcomes After Anti-reflux Surgery
Physiological Predictors of Clinical Outcomes After Anti-reflux Surgery
Gastro-oesophageal reflux disease (GORD) is a common condition, where acid from the stomach
 leaks up into the oesophagus (gullet) and causes symptoms such as heartburn and an unpleasant
 taste in the back of the mouth. GORD can often be controlled with self-help measures and
 medication. Occasionally, surgery to correct the problem may be needed.

 A laparoscopic fundoplication is a keyhole (laparoscopic) procedure which is a highly
 effective treatment. Although reflux-related symptoms are absent or well controlled in over
 85% of patients at 5 years after the operation, younger patients may have higher expectations
 that such an operation would hopefully last decades.

 Oesophageal physiology tests such as 24-hour catheter pH (potential of hydrogen) and
 impedance involve passing a small tube into oesophagus via patients' nose to monitor the
 presence of stomach content (acid or non-acid) in the oesophagus. The manometry test measures
 the pressures and coordination of pressure activity within the oesophagus. Bravo™ wireless pH
 monitoring uses a capsule that is attached to the oesophageal lining. These tests are often
 used as part of a pre-operative evaluation before anti-reflux surgery (ARS).

 Several measurements in these tests (also called parameters) could potentially anticipate
 clinical outcomes following anti-reflux surgery. The evidence for parameters like duration of
 acid exposure, number of reflux episodes and association with symptoms, pressures and
 co-ordination of pressure activity in the oesophagus, came from studies which were not
 designed in the most rigorous way to determine whether a cause-effect relation exists between
 treatment and outcome.

 This is a single centre, retrospective, observational study in which patients who had
 pre-operative physiology testing and anti-reflux surgery at a tertiary centre in the last 10
 years will be assessed for reflux symptoms and quality of life over the phone, based on three
 validated questionnaires. The study is designed to evaluate correlations between oesophageal
 physiology parameters and symptomatic response to ARS.
This is a single centre, retrospective, cross-sectional study on patients who had anti-reflux
 surgery and pre-operative oesophageal physiology testing over 10 years. The investigators
 anticipate the recruitment of up to 350 subjects over 18 months.

 Eligible patients will be contacted over the phone and asked whether they would be interested
 in joining the study. Candidates will be presented with details no less than the exact nature
 of the study, the implications and constraints of the protocol. Subjects will be made aware
 that no intervention will be made in this study, therefore taking part involves no risks or
 side effects. If all questions that satisfy inclusion and exclusion criteria are answered
 satisfactorily, and patients are happy to enter the study, participants will be consented
 verbally over the phone. It will be stated that the participant is free to withdraw from the
 study at any time for any reason without prejudice to future care, and with no obligation to
 give the reason for withdrawal.

 Once recruited the following assessments and interventions will take place:

 1. Patients will be assessed based on the Reflux Disease Questionnaire (RDQ) which is
 designed to assess the frequency and severity of heartburn, regurgitation and dyspeptic
 symptoms. Response options are scaled as Likert-type with scores for and severity. RDQ
 demonstrated validity and reliability in multiple languages and represents a viable
 instrument for assessing symptom severity and response to treatment.

 2. Patients will also be assessed based on The Reflux Symptoms Index (RSI) questionnaire
 which evaluates the presence and severity of laryngopharyngeal reflux (LPR). RSI can be
 completed in less than one minute. It is easily administered, highly reproducible and
 demonstrated design- and criteria-based validity in multiple languages.

 3. Participants will finally be evaluated based on the Gastroesophageal Reflux Disease
 Health-Related Quality of Life (GORD-HRQL) questionnaire which is aimed at typical
 reflux symptoms and impact on the daily living. The questionnaire can be easily given
 over the phone in less than 2 minutes. GORD-HRQL has been validated and is a reliable
 and practical tool in several languages.

 4. Data recorded will include the standard components of pre-operative oesophageal pH
 monitoring and high-resolution manometry, reflux symptoms scores, PPIs (proton pump
 inhibitors) usage, post-operative physiology studies and re-do anti-reflux surgery.

 5. Statistical analysis will involve multiple logistic regression and multiple linear
 regression models. Sensitivity and specificity of each predictor will be measured using
 the Receiver Operating Characteristic (ROC) curve analysis. A minimum of 350 patients
 for 5 predictors will define our sample size.
Inclusion Criteria:

 -  Males and non-pregnant females over the age of 18 years.

 -  Gastro-oesophageal symptoms in accordance with Montreal criteria49

 -  Patients who had oesophageal physiology testing at Guy's and St Thomas' NHS Foundation
 Trust

 -  Oesophageal manometry based on Chicago classification

 -  24-hour standard pH, impedance-pH and Bravo™

 -  Minimum 6 months post ARS and follow-up at GSTT

 -  Verbal consent over the phone

 Exclusion Criteria:

 -  Patients less than 18 years of age.

 -  Pregnancy at the time of interview

 -  Patients unable to comprehend or answer the questionnaires

 -  Oesophageal physiology tests performed in other centres