Symptom association probability does not reliably distinguish functional heartburn from reflux hypersensitivity

Area of Science:

• Gastroenterology
• Esophageal Physiology
• Diagnostic Accuracy

Background:

• Symptom association probability (SAP) is a proposed metric to differentiate reflux hypersensitivity from functional esophageal disorders.
• A positive SAP (SAP-positive) suggests gastro-oesophageal reflux disease (GERD) as the cause of persistent symptoms.

Purpose of the Study:

• To analyze the pH monitoring and symptom criteria that define a diagnosis of SAP-positivity.
• To evaluate the utility of SAP in distinguishing reflux hypersensitivity in PPI-refractory GERD patients.

Main Methods:

• Calculated SAP for 205 patients with refractory GERD symptoms undergoing wireless pH monitoring.
• Grouped patients into pH-negative/no esophagitis, pH-positive/no esophagitis, and esophagitis groups.
• Analyzed symptom and reflux event associations using 2x2 tables and quantified intervals distinguishing SAP-positive from SAP-negative.

Main Results:

• Small differences in SAP parameters distinguished SAP-positive diagnoses across groups (0.48% to 2.98%).
• Significant day-to-day variability in SAP values was observed, particularly in the esophagitis-positive group.
• Pre-surgery SAP did not correlate with the success of anti-reflux surgery.

Conclusions:

• Symptom association probability (SAP) is not accurate for distinguishing reflux hypersensitivity from functional esophageal symptoms in PPI-refractory GERD.
• The diagnostic criteria for SAP-positivity require further refinement for clinical application.