Gastroenterology
Volume 130, Issue 3 , Pages 988-989, March 2006

Pressure Details From the Weight-Challenged Gastroesophageal Junction: More Than the Usual Suspects

  • Radu Tutuian

      Affiliations

    • Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Zurich, Zurich, Switzerland
    • Corresponding Author InformationAddress reprint requests to: Radu Tutuian, MD, Head, Gastrointestinal Function Unit, Division of Gastroenterology/Hepatology, University of Zurich, Ramistr. 100, CH-8091 Zurich, Switzerland. fax: (41) 44 255 4503.
    • ,
  • Donald O. Castell

      Affiliations

    • Division of Gastroenterology—Hepatology, Medical University of South Carolina Charleston, South Carolina, USA

Article Outline

 

Approximately 40% of the adult US population admits experiencing heartburn, the hallmark symptom of gastroesophageal reflux disease (GERD).1, 2 Currently, more than 60% of the adult US population are overweight or obese (ie, body mass index; BMI >25 kg/m2).3 The high prevalence of these 2 conditions appropriately raises the question of a possible association between them. To date, this association remains controversial although there are studies indicating a positive association.4, 5, 6

In the current issue of Gastroenterology, Pandolfino et al7 report on the challenge to the gastroesophageal junction attributed to obesity. Analyzing high-resolution manometry tracings and anthropometric data from 285 consecutive patients with GERD symptoms, dysphagia (without reflux), and atypical symptoms, the authors analyze the relationship between BMI and waist circumference and intragastric pressure, intraesophageal pressure, gastroesophageal pressure gradient (GEPG), lower esophageal sphincter (LES) and diaphragmatic crura separation and intrahiatal pressure. In addition, the evaluation included the effect of esophageal gastric junction pressure profile on GERD symptoms. One of the more fascinating observations in this report is the greater waist circumference in the males studied and the resultant greater abnormalities in pressure findings than that noted in females of a similar BMI. Pandolfino et al7 are to be congratulated for providing a study in which they have incorporated novel advanced technology to help clarify the pressure relationships around the esophagogastric junction and stages of obesity in a large number of patients.

This report is replete with statistical analyses (both univariant and multivariant) providing numerous correlation coefficients, primarily between BMI or waist circumference and pressure relationships measured by high-resolution manometry. The relative statistical overload might be acceptable were it not for the overenthusiasm of the authors in interpretation of the findings. The best correlation obtained in this study was an R value of 0.64 with the lowest being only 0.17. The authors have considered these to provide evidence of a “strong” correlation between the measured parameters. That they were all significant as judged by the associated P value is no surprise considering the large number (285) of observations. One must remember that the P value in the case of correlation only defines if there is a statistical linear relationship between the 2 variables; it does not provide any indication of the relative strength of the relationship. Even the best R value, 0.64, when squared indicates that only approximately 41% of changes in the X axis values can be attributed to a relationship to the Y axis variables. This can be readily seen when one examines the related figures, which show a considerable degree of variability within the correlation plots. Thus, one should be somewhat cautious in the interpretation of the studies provided in this interesting report. Failure to appreciate this aspect of the linear regression analysis leads to an even greater sin of suggesting that one could predict unit changes in pressures related to changes in BMI or waist circumference

Unfortunately the study does not include quantitative reflux data. Data on the proportion of GERD and non-GERD patients in the 3 BMI groups and the correlation of symptom severity and BMI, gastroesophageal pressure gradient, or gastroesophageal junction separation are difficult to find. The authors are also somewhat loose in their application of the term “dose-response.” In this study, there is no dose and no response. Rather, the relationships analyzed should be described as “body index – pressure” relationships. The message of the study would have been stronger if objective reflux data (ie, pH or impedance-pH parameters) would have been measured. Nevertheless, the study highlights the potential of high-resolution manometry to evaluate pressure profiles at the gastroesophageal junction. An even more elegant approach would have been evaluating pressure changes in the gastroesophageal junction and gastroesophageal fluid flow using combined high-resolution manometry and high-resolution impedance as previously performed by this group.5 Using such a setting would have allowed evaluating with higher accuracy the interplay between pressures and bolus flow without the use of radiation.

Overall, Pandolfino et al7 are to be complimented for using the newest modern manometric technology to open our eyes to relationships of obesity to pressure derangements at the EG junction conducive to the development of gastroesophageal reflux. One major unanswered piece to the relationship between obesity and reflux not addressed by this report is whether the predominant reflux symptoms in such patients are due to the obesity per se or due to the dietary habits that have led to the obesity. The insights on the relationship between obesity and gastroesophageal junction dynamics invite further investigations of the pathophysiologic mechanisms of GERD. The available clinical tools and nonradiation imaging techniques8 should allow a better understanding of the interplay between pressure changes, structure dynamics and fluid flow leading to gastroesophageal reflux.

Back to Article Outline

References 

  1. Locke GR , Talley NJ , Fett SL , Zinsmeister AR , Melton LJ . Prevalence and clinical spectrum of gastroesophageal reflux (a population-based study in Olmsted County, Minnesota) . Gastroenterology . 1997;112:1448–1456
  2. Shaker R , Castell DO , Schoenfeld PS , Spechler SJ . Nighttime heartburn is an under-appreciated clinical problem that impacts sleep and daytime function (the results of a Gallup survey conducted on behalf of the American Gastroenterological Association) . Am J Gastroenterol . 2003;98:1487–1493
  3. Hedley AA , Ogden CL , Johnson CL , Carroll MD , Curtin LR , Flegal KM . Prevalence of overweight and obesity among US children, adolescents, and adults, 1999–2002 . JAMA . 2004;291:2847–2850
  4. El-Serag HB , Graham DY , Satia JA , Rabeneck L . Obesity is an independent risk factor for GERD symptoms and erosive esophagitis . Am J Gastroenterol . 2005;100:1243–1250
  5. Kouklakis G , Moschos J , Kountouras J , Mpoumponaris A , Molyvas E , Minopoulos G . Relationship between obesity and gastroesophageal reflux disease as recorded by 3-hour esophageal pH monitoring . Rom J Gastroenterol . 2005;14:117–121
  6. Hampel H , Abraham NS , El-Serag HB . Meta-analysis (obesity and the risk for gastroesophageal reflux disease and its complications) . Ann Intern Med . 2005;143:199–211
  7. Pandolfino JE , El-Serag HB , Zhang Q , Shah N , Ghosh SK , Kahrilas PJ . Obesity (a challenge to esophageal gastric junction integrity) . Gastroenterology . 2006;130:639–649
  8. Schwizer W , Fox M , Steingotter A . Non-invasive investigation of gastrointestinal functions with magnetic resonance imaging (towards an “ideal” investigation of gastrointestinal function) . Gut . 2003;52(Suppl 4):iv34–iv39

PII: S0016-5085(06)00195-8

doi:10.1053/j.gastro.2006.01.069

Refers to article:

  • Obesity: A Challenge to Esophagogastric Junction Integrity , 13 December 2005

    John E. Pandolfino, Hashem B. El–Serag, Qing Zhang, Nimeesh Shah, Sudip K. Ghosh, Peter J. Kahrilas
    Gastroenterology March 2006 (Vol. 130, Issue 3, Pages 639-649)

Gastroenterology
Volume 130, Issue 3 , Pages 988-989, March 2006

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