We read with interest the article by Jonasson et al.[1] on the use of a symptom-based questionnaire (GerdQ) as diagnostic tool for gastro-oesophageal reflux disease (GERD). The authors concluded that GerdQ is a valid complementary tool for the diagnosis of GERD, objectively identified by erosive oesophagitis (EO) at endoscopy and/or pathological oesophageal acid exposure and/or positive symptom association probability with acid reflux (SAP+ if ≥95%), and can be used to reduce the need for upper endoscopy and improve resource utilisation.

Moreover, the study provided additional relevant data on the limited value of the proton pump inhibitor trial as a diagnostic test for GERD, as we have recently demonstrated with the current state-of-the-art technique to diagnose GERD.[2, 3] However, we believe that the strength of their experimental findings would have improved if the results of symptom index (SI) were also reported.

Indeed, it is still debated which symptom association index should be better used in clinical practice. Ward et al. firstly introduced the SI that has the advantage to be very easy to calculate, but has a major shortcoming as it does not take into account the total number of reflux episodes with the likelihood risk that a symptom is found to be associated with reflux by chance.[4] On the other hand, the more recent SAP, as a statistical parameter, is not brought by chance and better explores the relationship between symptoms and reflux,[5] but recent studies have questioned this index.[6]

Given the above data, we believe that the use of both symptom indexes, which can be calculated using both pH-metry and impedance-pH monitoring, are necessary to corroborate the final diagnosis of GERD. Moreover, at variance with the caution suggested by Slaughter et al., we have recently shown in patients with EO and non-erosive reflux disease (NERD) that they are both helpful in increasing the possibility of identifying patients with reflux disease.[7, 8]

Therefore, in conclusion, we believe that both symptom indexes should be included in pathophysiological studies using impedance-pH monitoring to improve the diagnostic yield.


  1. Top of page
  2. Acknowledgement
  3. References

Declaration of personal and funding interests: None.


  1. Top of page
  2. Acknowledgement
  3. References
  • 1
    Jonasson C, Wernersson B, Hoff DA, et al. Validation of the GerdQ questionnaire for the diagnosis of gastro-oesophageal reflux disease. Aliment Pharmacol Ther 2013; 37: 56472.
  • 2
    Savarino E, Marabotto E, Zentilin P, et al. The added value of impedance-pH monitoring to Rome III criteria in distinguishing functional heartburn from non-erosive reflux disease. Dig Liver Dis 2011; 43: 5427.
  • 3
    Savarino E, Pohl D, Zentilin P, et al. Functional heartburn has more in common with functional dyspepsia than with non-erosive reflux disease. Gut 2009; 58: 118591.
  • 4
    Ward BW, Wu WC, Richter JE, et al. Ambulatory 24-hour esophageal pH monitoring. Technology searching for a clinical application. J Clin Gastroenterol 1986; 8(Suppl. 1): 5967.
  • 5
    Weusten BL, Roelofs JM, Akkermans LM, et al. The symptom-association probability: an improved method for symptom analysis of 24-hour esophageal pH data. Gastroenterology 1994; 107: 17415.
  • 6
    Slaughter JC, Goutte M, Rymer JA, et al. Caution about overinterpretation of symptom indexes in reflux monitoring for refractory gastroesophageal reflux disease. Clin Gastroenterol Hepatol 2011; 9: 86874.
  • 7
    Savarino E, Tutuian R, Zentilin P, et al. Characteristics of reflux episodes and symptom association in patients with erosive esophagitis and nonerosive reflux disease: study using combined impedance-pH off therapy. Am J Gastroenterol 2010; 105: 105361.
  • 8
    Savarino E, Zentilin P, Tutuian R, et al. The role of nonacid reflux in NERD: lessons learned from impedance-pH monitoring in 150 patients off therapy. Am J Gastroenterol 2008; 103: 268593.
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