This article is more than 5 years old. Information may no longer be current.
Esophageal pH-impedance monitoring parameters predict GERD outcomes
Click Here to Manage Email Alerts
Increased acid exposure time and symptom-reflux correlation detected by esophageal pH-impedance monitoring predicted response to antireflux therapy among patients with GERD, according to recent study data.
“We designed this study to look for parameters on pH-impedance testing that would predict management outcome, and in doing so, provide us with parameters that would provide best evidence for GERD,” C. Prakash Gyawali, MD, from Washington University School of Medicine, St. Louis, Missouri, told Healio Gastroenterology.
C. Prakash Gyawali
To identify pH-impedance parameters predictive of symptomatic outcomes in patients with GERD who underwent medical and surgical antireflux therapy, and also to determine whether testing on or off antisecretory therapy is superior, Gyawali and colleagues performed a prospective study involving 187 patients with GERD.
“We collected symptom data up front, and allowed treating physicians to manage the patients without direction from the study,” Gyawali said. “After a mean 3.5 year follow up period, we contacted the patients and collected symptom data once again to decide who got better and who didn't, and what kind of treatment they underwent.”
All of the patients (mean age, 53.8 ± 0.9 years; 70.6% female) had persistent symptoms despite antisecretory therapy and were referred for pH-impedance testing from January 2005 to August 2010. Symptom questionnaires assessed dominant symptom intensity and global symptom severity at baseline and follow-up evaluation, data were collected from pH impedance tests, and univariate and multivariate analyses determined factors associated with changes in symptom burden after therapy.
Overall, 49.7% of patients underwent pH-impedance testing on proton pump inhibitor therapy, and 68.4% were managed medically while the remainder underwent antireflux surgery. After a follow-up period of 39.9 ± 1.3 months, dominant symptom intensity and global symptom severity scores improved by 57.8% and 55.2%, respectively (P < .05).
Univariate analysis showed that abnormal acid exposure time predicted improved dominant symptom intensity and global symptom severity scores (both P ≤ .049). Reflux exposure time and symptom association probability from impedance-detected reflux events also predicted improved dominant symptom intensity and global symptom severity (P ≤ .03). Multivariate analysis showed abnormal acid exposure time predicted linear improvement in dominant symptom intensity (RR = 2.3; 95% CI, 0.3-4.3) and global symptom severity (RR = 17.1; 95% CI, 6.3-27.9), and impedance-detected symptom association probability also predicted linear improvement in global symptom severity (RR = 13.4; 95% CI, 1.6-25.1). Older age and testing performed off PPI therapy also were predictive of symptomatic outcome.
“First, information from pH impedance testing performed off PPI therapy provided best evidence to predict management outcome,” Gyawali said. “Our main study findings were that abnormal acid parameters provided best evidence for symptom improvement with antireflux therapy, information that can be obtained from the pH part of the pH impedance study. However, the impedance part of the study was more precise in symptom reflux association, and the calculated symptom reflux probability from impedance detected reflux events also predicted outcome.”
The researchers concluded that “impedance-based reflux parameters complement but do not replace acid-based parameters in predicting symptom outcome from both medical and surgical antireflux therapy.”
Michael F. Vaezi
“It is important to recognize that the use of empiric therapy with PPIs has changed the role of esophageal reflux testing. The most important value of pH or impedance monitoring is no longer defining presence of GERD but rather its exclusion,” Michael F. Vaezi, MD, PhD, MSc, from the Center for Swallowing and Esophageal Disorders at Vanderbilt University Medical Center in Nashville, Tennessee, wrote in an accompanying editorial. He calls for a simplified approach to testing based on available data in which clinicians will refrain from using measures they know “are suboptimal at best. What this field needs is a randomized controlled, outcome driven study to assess the role of pre-therapy impedance parameters in predicting treatment outcome.” – by Adam Leitenberger
Disclosure: The researchers and Vaezi report no relevant financial disclosures.
Editor’s Note: This article was updated on May 5 to reflect additional information.
Click Here to Manage Email Alerts