The Role of Symptom Association Analysis in Gastroesophageal Reflux Testing

Gastroesophageal reflux disease is characterized by the reflux of gastric contents into the esophagus with an estimated worldwide prevalence of 8%-33%. The current paradigm in gastroesophageal reflux disease diagnosis relies on recognition of symptoms and/or the presence of mucosal disease at the time of esophagogastroduodenoscopy. Recognition of symptoms, however, can arise with challenges, particularly when patients complain of less typical symptoms. Since first reported in 1969 by Spencer et al., the application of prolonged intraesophageal pH monitoring to identify pathologic reflux has evolved considerably. Utility of pH monitoring aims to investigate the degree of acid burden and frequency of reflux episode, and the relationship between symptoms and acid reflux events. This relationship is represented by either the Symptom Index, Symptom Sensitivity Index, Symptom Association Probability, or Ghillebert Probability Estimate. This article reviews symptom-association analysis during esophageal reflux testing, covering the literature on current methods of reflux testing, interpretation of symptom association, and practical issues that can arise during symptom analysis.