Tag Archives: Gastroesophageal Reflux

Gastroesophageal Reflux: I know it when I see it

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      According to Wikipedia, Justice Potter Stewart, in Jacobellis v. Ohio 378 U.S. 184 (1964) stated the following: I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description [“hard-core pornography”]; and perhaps I could never succeed in intelligibly doing so. But I know it when I see it, and the motion picture involved in this case is not that. [Emphasis added.]
     To some extent, ‘I know it when I see it’ has been the mantra about identifying gastroesophageal reflux for advocates for pH-impedance (pH-MII).  Enthusiasts have claimed that pH-MII is vastly superior to pH studies alone for many reasons including the ability to detect more GER episodes than conventional pH studies.  Yet, a major flaw has been a paucity of normative data.  To determine whether there is interobserver and intraobserver agreement in the interpretation of pH-MII, seven expert world groups collaborated on a study to analyze ten pediatric 24-hour tracings (J Pediatr 2012; 160: 441-6).
     Five of these studies were considered easy and five were more challenging due to less obvious features like low baselines, retrograde patterns during swallowing, and moving/crying artifacts.   Among 1242 liquid and mixed GER events, 490 (42%) were scored by the majority of observers.  The authors claim that this is “moderate agreement.”  The automated analysis (AA), not surprisingly, had much better agreement than manual analysis.   With AA there was 94% sensitivity rate and 74% specificity. When looking at AA alone, AA missed 6.5% of events scored by observer consensus and  30% of GER episodes recorded with AA were not detected by majority consensus.
     When looking at each pH-MII recording (Figure 2), there was poor agreement on whether the study was pathologic.  Only five of the studies had uniform agreement that the number of episodes (>73 GER episodes) were either pathologic or not. Those with agreement were all negative studies.  The authors conclude, though, that there was “substantial” agreement based on a mean kappa value of 0.70.
     A comparison to a previous pH-MII publication (Scand J Gastro 2011; 46: 271-6) notes that in this previous study, 83% of pH-MII recordings had a concordant symptom association probability despite underdetection of GER episodes with AA; it was recommended to use ‘AA when the symptom association was positive.  If symptom association was negative, they suggested manual analysis.’
    The conclusions from the current study:
  • ‘In theory, AA is favored over manual analysis due to reproducibility’
  • AA does not seem specific enough to ensure correct marking of GER episodes in infants and children yet
  • Consensus to refine AA needs to be reached …to retain confidence …in impedance

If this is the best that worldwide experts can do with this widespread technology, what does that mean for clinicians in practice?

Additional references:

Recent related posts:

The Medical Pendulum and Gastroesophageal Reflux

Unexplained chest pain

  • -Journal of Gastroenterology and Hepatology 2010;25:817-22. Has some normative pH-MII data.  ‘Can acid (pH) refluxes predict multichannel intraluminal impedance refluxes? A correlation study.’
  • -JPGN 2010; 50: 25. Reflux detected by Impedance does NOT determine fundoplication outcome. n=34.
  • -JPGN 2010; 52: 129. Review. No normative data. Using SAP>95% to correlate symptoms (better than SI or SSI). Main use is to study intractable pts to establish if nonacid reflux is contributing to symptoms.
  • -J Pediatr 2010; 157: 878 (“death of pH probe”), 949. Use of impedance in children. n=225. (70 were discarded). Notes lack of therapeutic possibilities for non-acid reflux.  Symptom index is + if >50%, SAP if >95%. Symptom index is number of symptoms with reflux episode divided by total number of symptom occurrences. SAP, symptom association probability, is a statistical tool that uses 2-minute windows throughout recording to correlate symptom and reflux event.  pH probe 2nd metal for infant -place 2cm above LES.  pH probe 3rd metal for child -place 3cm above LES
  • -Clin Gastro & Hep 2009; 7: 743. n=39 adults. Non-acid reflux events in patients on therapy correlated with acid reflux parameters when patients studied off therapy. Abnormal impedance parameters: total number of reflux events >63 (avg normal was 28). This study relied on # of reflux events more than SAP or SI. SAP or SI is problematic in patients who lack clinical response to PPIs.
  • -Gastroenterology 2009; 136 (suppl 1): S1896. n=143. #of events (not SI or SAP) is then most conservative estimate as well as the one with the highest likelihood of encompassing other symptom assoication parameters.
  • -J Pediatr 2009; 154: 248. n=50. a high # with normal pH had symptom correlation w GER events. (initial cohort was 80 –30 excluded due to problems with study or insufficient symptoms) SAP is superior for correlating symptoms.
  • -Clin Gastro & Hep 2008; 6: 840. Impedance is best tool -D Castell.; -Clin Gastro & Hep 2008; 6: 880.
  • -Clin Gastro & Hep 2008; 6: 482, 521. ‘Impedance/pH is best tool’. Pts who respond to PPIs likely due so due to its effect on chemostimulation; those who continue with symptoms may do so based on mechanostimulation -related to volumes in esophagus not due to acidity.
  • -J Pediatr 2006; 149: 216. Equal frequency of acid and non-acid reflux in 24 pts with asthma. No correlation identified with resp symptoms.
  • -Clin Gastro & Hep 2006; 4: 167. Impedance does not add to pH probe in UNTREATED patients.
  • -JPGN 2002; 34: 511, 519.
  • -Pediatrics 2006; 118: e299, 793. Impedance data in preterm infants. Asymptomatic and affected infants with similar impedance values and both have reflux to upper esophagus.

The Medical Pendulum and Gastroesophageal Reflux

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In so many areas of pediatric gastroenterology, there is a gradual development of enthusiasm for a medical treatment.  In the vast majority, the enthusiasm goes too far and closer scrutiny often determines a more limited role for this medical treatment or potential adverse effects that were not initially appreciated.  The latest example of this may well be with the use of proton pump inhibitors (PPIs) for gastroesophageal reflux disease, particularly in infants and individuals with asthma.  Although these medications may not have reached their apogee, more and more their effectiveness for so many ailments has been questioned.  In this month’s issue of JPGN, this is highlighted (JPGN 2012; 54: 8-14).  The article which emanates from the offices of the FDA discusses the fact that the usage of PPIs has increased 11-fold from 2002-2009 in infants <12months of age; 404,000 prescriptions were dispensed to 145,000 infants in the U.S. in 2009.    At the same time, althougth there have been four randomized controlled trials of PPIs in infants, NO studies have demonstrated the effectiveness of these drugs in this population.  As a consequence, the authors recommend that these drugs be restricted to infants with endoscopically-proven GERD/erosive esophagitis.  No other tools are sufficient to identify infants who are likely to respond.  Perhaps the reason why these agents work less well in infants is due to the fact that acid secretion is much less in infants than in children and adults.  For example, at 4months of life, average acid secretion rate in infants is ~27-fold lower than in adults (Am J Dig Dis 1969; 14: 400-14). As a consequence, their symptoms may not be responsive to acid reduction treatments.

Other related references on GERD in infancy:

–JPGN 2010; 50: 609-18. Pantoprazole helped improve symptoms but there were no significant differences compared to placeblo in withdrawal rates due to lack of efficacy. n=128.
-NASPGHAN 2009, Abstract#21. Meds/Rx of NICU pts did not shorten hospital stay or promote wt gain, n=1149.
–JPGN 2009; 49: 498. NASPGHAN GERD guidelines. “In infants and toddlers, there is no symptom or symptom complex that is diagnositc of GERD or predicts response to therapy.” Identical response to placebo (vs prevacid) in largest double-blind randomized study (54% at 4 weeks) (J Pediatrics 2009; 154: 514-20.)-Reflux is “not a common cause of unexplained crying. irritability..in otherwise healthy infants.” “There is no evidence to support the empiric use of acid suppression for the treatment of irritable infants.”

GERD and respiratory/ENT issues:

–Gastroenterology 2010; 139: 1887. PPIs decreased postnasal drainage compared to placebo. n=75. (50% vs 5%) age discrepancy in patient populations.
–Clin Gastro & Hep 2010; 8: 741 (excellent editorial), 770 (article on rabeprazole improving heartburn Sx in pts with laryngitis), n=82. Editorial suggests 1-2month trial of BID PPI and if not effective, then little to offer. May change when studies looking at surgery (after impedance) outcomes.
–Gastroenterology 2010; 139: 754. 716 (editorial). Acoustic cough & reflux. Study recorded cough during pH measurement. n=71. ‘causality cannot be established until effective treatment’ available.
–Gastroenterology 2009; 137: 1844. Critical review of below NEJM article. ‘a subset of asthmatics will have objective detection of GERD without typical symptoms…work by Amer Lung Assn suggests that twice daily PPI will not be helpful’..however, ‘perhaps 3-6months of PPI may still be reasonable until we can accurately identify subgroups of pts who may respond.’ –Gary Falk, Cleveland Clinic
–NEJM 2009; 360: 1487, 1551. Use of PPIs (nexium 40mg bid) in poorly-controlled asthma with no symptoms of GER –did not help w asthma control & pH studies were not predictive of response. n=412 adults. 40% c abnl pH studies in each group (nexium vs. placebo).
–Clin Gastro & Hep 2007; 5: 1379. Review of ENT findings and reflux.
–Am J Gastro 2007; 102: 716. Poor specificity of ENT findings for diagnosis of laryngopharyngeal reflux.
–Aliment Pharm Ther 2007; 25: 385-92. meta-analysis. Rx c PPIs not more effective than placebo in resolving ENT symptoms presumed to be due to GER. Editorial suggests some patients may benefit, but better tools are needed to identify them.

GERD and surgery:

–Gastroenterology 2011; 141: 1938.  LOTUS study in JAMA summarized in this review. (JAMA 2011; 305: 1969) Medical treatment outperformed surgery. 92% under control (remission) with long term medical Rx vs 85% with surgery & fewer side effects of medical treatment.
–Clin Gastro & Hepatology 2009; 7: 1292, 1264 (editorial). 12yr outcomes for surgery vs PPI. n=154 omeprazole, n=144 surgery. Similar long term outcome ~50% with long term remission.

–Pediatrics 2006; 118:1828. 48,665 antireflux surgeries done from 1996-2003 (~7000/yr) in US

–Clin Gastro & Hep 2006; 4: 299. Frequent complications post-op and frequent need for GERD meds.  Dysphagia in 19%, dilatation in 6%, repeat surgery in 2%, mortality in 0.8% (n=3145). 50% required GERD meds.

–Clin Gastro & Hep 2004; 2: 978-984. Pediatric study.  n=198.  63% required post-op treatment for recurrent GERD -retrospective review 1996-99.

Proton Pump Inhibitors and reported adverse effects:

-Risk of Hypomagnesemmia -2011. http://www.fda.gov/drugs/drugsafety/ucm245011.htm
–NEJM 2010; 363: 2114. large Denmark study. 5082 fetuses with PPI exposure (out of 840,968 live births). Risk of birth defects NOT increased with exposure during 1st trimester. Possible slight increase risk with preconception use except with omeprazole.
–Gastroenterology 2010; 139: 1115. Review of safety of PPIs.
–Gastroenterology 2010; 139: 93. n=167,000. PPIs associated with hip fracture risk, OR 1.3, in patients with other risk factors.
–Gastroenterology 2010; 138: 896-904. 5yrs of PPI -no increase risk in hip/spine fx.
–Arch Intern Med 2010; 170: 765-71, 747 (ed). PP not related to hip fx (n=161,806) women 50-79. INCREASE risk of spine fx, hazard risk 1.47
–Arch Intern Med 2010; 170: 772-8. PPIs increase risk of Clostridium difficile infection (hazard ratio 1.42 –42% increase in risk), n=1166.
–Arch Intern Med 2010; 170: 784-90. n=101,796. OR 1.74 for daily PPI, OR 2.36 if BID Rx; thus ~70% increase risk of nosocomial infection.
–Clin Gastro & Hep 2010; 8: 504. Increased bacterial overgrowth with PPI use.

-JAMA 2009; 301: 2120-2128. Use of PPIs associated with INCREASED hospital acquired pneumonia by ~30%. Could result in 180,000 HAP cases/yr with ~33,000 deaths. n+ 63,878 admissions, 52% on PPIs or H2RAs (83% PPIs, 17% H2RAs). H2RAs NOT associated with HAP cases.
–Gastroenterology 2009; 137: 80. PPIs induce acid-related symptoms in ~22% vs 7% of placebo in healthy volunteers.
–Ann Intern Med 2008; 149: 391-398. Risk for pneumonia associated with short-term PPI use, not long term
–Clin Gastro & Hep 2007; 5: 1418. Increases risk of bacterial gastroenteritis.
–JPGN 2007; 45: 395, 421. Increasing use of PPIs-4-fold from 2000-2003; 0.5% of all infants. No safety/efficacy data.
–J Pediatrics 2007; 150: 262. Long term use (up to 11yrs of usage) of PPIs in 166 children; minimal problems: 2 c nausea, 2 c skin rash, 1 c diarrhea, 1 c agitation.
–JAMA 2006; 296: 2947-53. Risk of bone fracture –odds ratio 1.44-2.65 with long-term PPI treatment (>1yr); UK study looked at 1.8million