Studies on gastroesophageal reflux disease

Gastroesophageal reflux is defined as the retrograde flow of gastric contents into the esophagus. The occurrence of reflux on itself is a physiological phenomenon. However, re?ux may become a disease (Gastroesophageal Reflux Disease or GERD) when it is responsible for symptoms sufficiently severe to impair quality of life and/or the development of esophageal mucosal lesions that can lead to a risk of long term complications. GERD should be considered a multi-factorial disease as no unifying pathogenesis has been found. Endoscopy seems to play a minor role in diagnosing GERD, as only a minority of GERD patients has acid-induced esophageal lesions. It is therefore essential to determine what is certain, namely that in GERD a causative relationship exists between gastroesophageal reflux episodes and reflux symptoms. For this purpose several types of analysis can be performed in which the relationship between symptoms and reflux episodes are expressed numerically in indices. Impedance-pH monitoring is the gold standard for gastroesophageal reflux detection. The manometric recording by means of a common cavity or/and pH recording alone are far inferior compared to impedance-pH. Recording of pH alone, despite its overestimation of reflux events, could still clinically be used to diagnose GERD when a symptom-association index such as the symptom association probability (SAP) is used. The SAP has shown to be less affected by the overestimation of reflux events. Secondly, in this thesis it is shown that this index is very reproducible independent of which reflux detection method is used. Diagnosing GERD in primary care is even more demanding than in secondary care as fewer resources are available. Most physicians only make use of a history taking added with a proton pump inhibitor test. When a good response to this acid-suppressing drug is found treatment with a PPI is continued. In this thesis it was found that patients with positive SAP the best response to PPI treatment independent of the amount of reflux present, physiological or pathological. Symptomatic reflux patients without any measurable evidence of GERD responded less favorably. The value of a PPI test as diagnostic tool in a symptomatic primary care population was however limited. The screening of GERD in primary care might improve when the PPI test is used in combination with a standardized questionnaire such as the Reflux Disease Questionnaire.