How Useful the Combined Impedance-pH Monitoring Is for Evaluation of Refractory Reflux Symptoms?: Author's Reply.

TO THE EDITOR: We would like to appreciate the interest shown on our study by Dr. Cho.1 Our response to her queries is as follows:

(1) We do agree that doubling the proton pump inhibitor (PPI) dose could be the most appropriate therapeutic strategy for gastroesophageal reflux disease (GERD) patients who are refractory to single dose of PPI before performing a pH-impedance measurement. However, previous studies challenged this approach and showed the majority of patients with persistent GERD symptoms on single PPI dose to experience symptoms continuously on even higher doses of PPIs.2,3 Our results showed that even though patients on standard PPI dose continued to report more symptoms during the study, the PPI dose seemed to have no impact on the symptom index analysis.4 This finding could imply that increase of the PPI dose should not be the solution in patients with refractory GERD like symptoms and that other causes (ie, functional heartburn and hypersensitive esophagus) could explain the origin of symptoms.

Moreover, in every day clinical practice, escalation of the dose is sometimes problematic. In our study, the majority of our population was referred by others and the low rate of double dose PPI usage reflects the absence of reimbursement for PPIs above the standard dose in Greece.

(2) We also agree that in GERD patients with atypical symptoms, pH-impedance monitoring is better to be performed while they are off medication. As we had mentioned in the article, our patient population was inhomogeneous. Many patients reported both typical and atypical symptoms, whereas others reported only atypical symptoms. It is clear that this practice influenced the sensitivity and clinical impact of pH-impedance monitoring. Choosing the most prevalent symptom could be a better surrogate index. However, it is widely accepted that the majority of patients report more than one symptom. Large population-based studies have shown presence of ENT and pulmonary symptoms among patients with reflux symptoms.5,6

As pH-impedance monitoring is a new technique that tries to find its position in the everyday clinical practice, further studies are needed to evaluate its clinical impact and usefulness.