Impedance recommendations from PIG

The ESPGHAN Pediatric Impedance Group (PIG) has published a review/consensus statement on the use of pH-Impedance monitoring (MII-pH) in children (JPGN 2012; 55: 230-34).

Conclusions from this group:

  • MII-pH provides more information than conventional pH probe.  Whether this information will “inform prognosis, or predict response to therapy in pediatric patients has yet to be determined”
  • ‘As long as there is no effective medical therapy for weakly acid and nonacid reflux, the clinical relevance of MII-pH remains debatable’
  • “There are no data on the results of antireflux surgery based solely on the detection of weakly acid and nonacid reflux”
  • MII-pH is investigational technique needing standardization before routine diagnostic use can be recommended.
  • Major indications: need to identify weakly acid and nonacid reflux, persisting symptoms during antireflux treatment, use in identifying rumination syndrome, and research
  • Limitations of MII-pH: high cost, limited contribution to change in medical care, lack of evidence-based parameters for assessment of GER

Related blog entries:

Gastroesophageal Reflux: I know it when I see it

Treating reflux does not help asthma

The Medical Pendulum and Gastroesophageal Reflux

A double whammy –obesity and GERD

“A double whammy is when something causes two problems at the same time, or when two setbacks occur at the same time.”  Double whammy – Idiom Definition – UsingEnglish.com

Obesity probably doesn’t fit this definition strictly because it causes a lot more than two setbacks.  However, obesity clearly causes its own set of problems and, even in childhood, contributes to the development of gastroesophageal reflux disease (GERD) (JPGN 2012; 55: 72-75).

This study consisted of 153 healthy children from a well-child clinic; among this group 31 were obese and 122 were nonobese.  All caregivers completed a reflux questionnaire.  The reflux symptomatic score was significantly higher in children with waist circumference (WC) >90th percentile compared with those <75th percentile.  Furthermore, the rise in GERD symptoms (heartburn, epigastric pain, and regurgitation) was shown to rise progressively with increasing BMI and WC.

One of the shortcomings of the study was the use of a questionnaire that has not been validated for assessment of reflux symptoms in children (according to the authors, none are available in children); though, this questionnaire has been used in a few prior publications.

More references on GERD and obesity:

  • -Gastroenterology 2010; 139: 1902, 1823.. Abdominal visceral adipose tissue increases risk for Erosive esophagitis.
  • -Ann Intern Med 2005; 143: 199-211. Pooled studies showed GERD symptoms with ORs of 1.43 c BMI 25-30 & 1.94 for > 30. OR for esophagitis was 1.76 for BMI>25 & increased risk of adenoca of 1.68-2.02
  • -Gastroenterology 2006; 130: 1925-6.  Obese youth have more reflux symptoms as with adults.

Previous post on GERD and asthma:

Treating reflux does not help asthma

Do medicines work for GERD infants?

“Absence of evidence is not evidence of absence.” Carl Sagan

If medicines work for infantile GERD, it is difficult to prove (Winter H, et alJPGN 2012; 55: 14-20).  The cited study is the latest having difficulty proving that proton pump inhibitors are effective in infants.  In this randomized, double-blind, placebo-controlled multinational study from 33 centers, 98 infants (1-11 months) were enrolled.  My colleague, Dr. Benjamin Gold, was one of the researchers.  Initially, a 2-week open-label treatment was given which was followed by a 4-week randomized phase.   Study participants had to have a clinical diagnosis of GERD with at least one GERD symptom  –at least twice per week in a 4-week period:

  • vomiting/regurgitation
  • irritability
  • supraesophageal manifestations (cough, wheeze, stridor)
  • respiratory symptoms triggered by feedings
  • feeding difficulties

The treatment administered was weight-based dosing of esomeprazole:

  • 3-5 kg:     2.5mg
  • 5-7.5kg    5mg
  • 7.5-12kg  10mg

Daily symptoms were captured with an interactive voice response system.  Among the initial 98 patients enrolled, 80 reached the randomization phase.  During the initial 2-week period, 81 (82.7%) had symptom improvement based on physician global assessment.  During the double-blind phase, 48.8% of placebo-treated patients and 38.5% of esomeprazole-treated patients discontinued therapy due to symptom worsening.  While the time for discontinuing esomeprazole was longer in a posthoc analysis, the primary outcome, discontinuation rate, was not significantly different.

So what is the reason that this was a negative study?  While the reasons are unclear, all of the following are possible:

  • Patient selection/lack of accurate diagnosis.  Mixed-population was recruited for the study –though this type of population is similar to clinical practice.
  • Dose of esomeprazole.
  • Inadequately powered study.  If the effectiveness of PPIs is small, a much larger population is needed.
  • Maybe these agents don’t work in infants.  Infants secrete less acid than children and adults; thus, acid blockers may not work as well. (The Medical Pendulum and Gastroesophageal Reflux)

Why not give PPIs even if they don’t work?  The previous link discusses many of the potential adverse problems that are possible with medical treatment of GERD. However, even if a medicine does not harm does not mean you should do something because it ‘might’ do some good.  An example of this is the apocryphal tale of the famous pianist who died one day in the middle of a recital. (I saw this in a journal article but cannot remember the reference.)  The manager came out to announce his death.  A man in the audience shouts, ‘Give him an enema.’ Initially, the manager tries to ignore him. After the man yells this three times, the manager responds, ‘the poor man is dead…what good will an enema do?’ The voice replies, ‘What harm will it do?

Additional references:

  • -JPGN 2010; 50: 609-18. Pantoprazole helped improve symptoms but there were no significant differences compared to placebo 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. Abstract#26. prevacid more effective than ranitidine in infants.
  • -J Pediatr 2009; 155: 601 (letter). Should not be used to treat symptoms unless proven to be reflux.
  • -JPGN 2009; 49: 498. GERD guidelines.  “In infants and toddlers, there is no symptom or symptom complex that is diagnostic of GERD or predicts a response to therapy.” Identical response to placebo (vs prevacid) in largest double-blind randomized study (54% at 4 weeks) (J Pediatr 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.”

Regurgitation harder to treat than heartburn, especially for NERDs

While all pediatric gastroenterologists know that the title of this blog entry is right, it is helpful to have data.

A recent study (Clin Gastroenterol Hepatol 2012; 10: 612-19) used a reflux questionnaire to evaluate responsiveness of regurgitation from 2 randomized controlled trials.  The trials compared a newer acid blocker (AZD0865 dosed at 25-75 mg/day)) to esomeprazole (20-40 mg/day).  Patients had either non-erosive reflux disease (NERD , n=1460),  or reflux esophagitis, (RE, n=1314).  Inclusion criteria included the presence of substernal burning for ≥4 days/week.

Regurgitation-taste (RT), defined as an “acid taste in the mouth,” or regurgitation-movement (RM), defined as an “unpleasant movement of material upwards from the stomach” were analyzed.  Among NERD patients, either or both symptoms were present in 53% at baseline compared with 54% among the RE group.  In both NERD and RE patients, the presence of these regurgitation symptoms was associated with a poorer response to therapy.

  • Complete response of NERD patients with regurgitation symptoms:  RT 34%, RM 26%; in comparison to heartburn response of NERD patients which was 49%
  • Complete response of RE patients with regurgitation symptoms:  RT 44%, RM 33%; in comparison to heartburn response of NERD patients which was 55%

Additional references/blog entries:

Proton pump inhibitors–infection risk with cirrhosis

In a previous post (The Medical Pendulum and Gastroesophageal Reflux), I note that enthusiasm for proton pump inhibitors has started to wane.  In addition, a significant number of reported of potential side effects were referenced.  Another potential adverse effect is increasing the rate of spontaneous bacterial peritonitis (SBP) in patients with cirrhosis (Clin Gastroenterol Hepatol 2012; 10: 422-27).

This retrospective study examined 65 hospitalized cirrhotic patients with paracentesis-proven SBP between 2006-2009 and compared them to 65 contemporaneous hospitalized cirrhotic patients without SBP.   Patients with SBP had a higher incidence of use of PPI within previous 7 days: 71% versus 42%.  Of patients with SBP receiving PPI, the authors state that 68% did not have a documented indication for PPI use.

Additional references/previous posts:

  • Treating reflux does not help asthma
  • -Risk of Hypomagnesemmia -2011. http://www.fda.gov/drugs/drugsafety/ucm245011.htm
  • 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. 5 yrs of PPI -no increase risk in hip/spine fx.
  • Arch Intern Med 2010; 170: 765-71, 747 (ed). PPI 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.

Preventing Cancer in patients with Barrett’s Esophagus

Though Barrett’s esophagus is rare in pediatric gastroenterology, concerns about esophageal cancer are fairly frequent.  In addition, some conditions that increase the risk of esophageal adenocarcinoma start in childhood.

One way to lessen the risk of Barrett’s esophagus in adults is through the use of medications (Gastroenterology 2012; 142: 442-52).  This study was a pooled analysis of six population-based trials with a total of 1226 esophageal adenocarcinoma (EAC) patients and 1140 esophagogastric junctional adenocarcinoma (EGJA) patients.  NSAIDs (aspirin and nonaspirin) lowered the risk of both EAC and EGJA, with OR of 0.68 and 0.83 respectively.

Although this study suggests a possible role for NSAIDs in preventing cancer in patients with Barrett’s esophagus, the risks and benefits for this intervention need to be individualized.

Related previous blog post: More bad news for smokers

Additional references:

  • -Gastroenterology 2011; 141: 2000. Lower risk of Barrett’s in pts taking NSAIDs & statins. n=570.
  • -Gastroenterology 2011; 141: 1179. Overall, patients with BE and LGD have a low annual incidence of EAC, similar to nondysplastic BE. There are no risk factors for progression and there is significant interobserver variation in diagnosis, even among expert pathologists.
  • -NEJM 2011; 365: 1375. Large Danish study, n=11028. Lower incidence of Barrett’s than previous estimates. Relative risk of 11.3 compared to general population for adenoca of Esophagus with absolute annual risk of 0.12%. Barrett’s patients have the same life expectancy as general population (ed. pg 1437). Detecting cancer only ~1 in 1460 scopes with screening whereas Barrett’s detected in 10% of pts.
  • -Gastroenterology 2011; 141: 417, 460. Durable effects of ablation, n=127..
  • -Gastroenterology 2011; 140: 1084. AGA statement on Barrett’s . Recs screening only in those with multiple risk factors (age 50, male, chronic GERD, white, incr BMI)
  • -Clin Gastro & Hep 2010; 8: 565. Guidelines suggest that screening for Barrett’s is not justified w/o alarm symptoms (dysphagia, odynophagia, wt loss, anemia, hematemesis)
  • -Gastroenterology 2010; 138: 2260. n=11,823. Decrease risk of esophageal adenoCa in patients taking NSAIDs & statins.
  • -Gastroenterology 2010; 138: 854. Nice review.
  • -Gastroenterology 2010; 138: 5. Survival equivalent to general population according to Mayo study, n=366. In Barrett’s patients, leading cause of death was cardiovascular (28%). Esophageal cancer resulted in 7% of deaths. Study presented at ACG Oct 26, 2009.
  • -Clin Gastro & Hepatology 2009; 7: 1266. no benefit from surgery for Barrett’s & unclear if chemoprevention works.
  • -Gastroenterology 2009; 137: 763. Suggests surveillance with Barrett’s is not beneficial.
  • -NEJM 2009; 360: 2277, 2353.. Radiofrequency ablation can be effective.
  • -Gut 2008; 57: 1200-06. Utility of endoscopic Rx.
  • -Clin Gastro & Hep 2008; 6: 1206; editorials: 1180, 1181, 1183.. n=2107 with Barrett’s. 79 w surgery and 80 w endoscopic Rx.
  • -Gastro & Hep 2006; 2: 468. 2-8% of pts in general population have Barrett’s. >90% of ptsc Barretts will never develop cancer. Screening has not been proven to be effective in lowering rate of death from cancer. ~40% of US population has heartburn; only 8000-9000/yr develop esoph adenoCa. Also, the presence of Barrett esophagus does not decrease life expectancy.
  • -Gastroenterology 2005; 129: 1825-31. 1.6% incidence of BE in adult Swedish population. Alcohol, smoking increase risk.

Treating reflux does not help asthma

Studies in adults have looked at the use of PPIs for asthma and have not shown improvement (see references below).  Now a trial of lansoprazole suggests the same is true in children (JAMA 2012; 307: 373-81).  This study was a randomized double-blind placebo-controlled study of 306 children with a mean age of 11; the participants were recruited from 19 academic medical centers in the US.  149 children received lansoprazole and 157 received placebo.  The dose of lansoprazole was 15mg in patients weighing less than 30kg, and 30mg in those weighing more than 30kg.

Those treated with lansoprazole did no better than placebo with regard to symptoms and lung function.  The main outcome was the asthma control questionnaire (ACQ) score. The lansoprazole group had a mean change in this score of 0.2 units which was not a meaningful change. More precise measures of lung function including forced expiratory volume also did not differ.

In a subgroup of 115 patients who had esophageal pH studies, the prevalence of GER was 43%.  Yet, no treatment effect for lansoprazole was observed for any asthma outcome.

Not only did lansoprazole not help, the treatment group experienced more adverse effects, including respiratory infections (relative risk 1.3), sore throats (RR 1.3), and episodes of bronchitis (RR 2.2).  Though not statistically significant, the treatment group had more activity-related fractures, six compared to one in the placebo group.

This study took several years to complete (2007-2010).  I congratulate the authors, especially the third author Benjamin Gold, for this excellent work.

http://www.ccdhc.org/doctors/gold.html

Additional references:

The Medical Pendulum and Gastroesophageal Reflux

GERD and respiratory/ENT issues:

  • 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.
  • 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.

Gastroesophageal Reflux: I know it when I see it

      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.