Prolonged acid reflux monitoring using acid exposure time and DeMeester score: two days are not enough.

Background: Wireless pH monitoring allows for a definitive GERD diagnosis, which is essential for optimal medical or surgical management of the patient. However, there is no guideline recommendation on whether prolonged pH testing (72 or 96 h) provides additional benefit when compared to the standard 48-h testing. We aimed to assess whether prolonged pH monitoring diagnoses more patients with GERD, as well as compare the DeMeester score to acid exposure time as diagnostic criteria for GERD.

Methods: This was a retrospective analysis of consecutive adult patients who underwent wireless esophageal pH monitoring between August 2018 and July 2021. The primary outcome was the additional diagnoses of GERD (predominant acid exposure pattern) in patients who underwent 48-h versus 96-h pH monitoring. Secondary outcomes included comparison of the DeMeester score to acid exposure time and internal agreement between the first and second 48-h blocks of a prolonged 96-h pH study.

Results: When comparing 48-h versus 96-h pH testing, the prolonged monitoring group was more likely to have a predominant reflux pattern and thus be diagnosed with definitive GERD by elevated DeMeester score (58.8% vs. 40.8%, p = 0.003) or acid exposure time > 6% (44.7% vs. 32.4%, p = 0.039). For patients who underwent prolonged testing, the results of monitoring beyond 48 h led to a clinically meaningful change in study interpretation in 24.8% of patients. The study data from Days 3 to 4 yielded only a 56.6% agreement with the first 2 days.

Conclusions: In patients undergoing extended pH monitoring, almost half were found to have an abnormal pH study after a normal study on Day 1. An additional 25% of patients had a change in study interpretation by extending the study beyond 48 h. Our findings suggest only 48 h of pH monitoring will miss a diagnosis of GERD in a clinically important number of patients.