Poor effectiveness of proton pump inhibitors in non‐erosive reflux disease: the truth in the end!

Despite acid secretion being normal in the majority of patients with gastro‐esophageal reflux disease (GERD) or Barrett’s esophagus, acid inhibition represents the mainstay of treatment for both these conditions, with the aim of reducing the aggressive nature of the refluxate toward the esophageal mucosa. Proton pump inhibitors (PPIs) represent, therefore, the first choice medical treatment for GERD, in that they are able to provide an 80–85% healing rate for esophageal lesions, a 56–76% symptom relief and also reduce the incidence of complications, such as strictures as well as dysplasia and adenocarcinoma in Barrett’s esophagus. According to a widely quoted systematic review, compared to patients with erosive esophagitis, patients with non‐erosive reflux disease (i.e., NERD) display a reduced symptom relief with PPIs, with about 20% reduction of therapeutic gain. In this issue of NeuroGastroenterology & Motility, Weijenborg et al. address for the first time the PPI efficacy in subpopulations of patients with NERD. The study shows clearly that, when the diagnosis is accurately made by including a functional test, NERD patients respond to PPI therapy in a similar way to those with erosive disease. Although not as frequent as previously suggested, however, PPI‐refractory heartburn does exist. Some 20% (range: 15–27%) of correctly diagnosed and appropriately treated patients do not respond to PPI treatment at standard doses. Although the pathophysiology underlying PPI failure in GERD is complex and likely multifactorial, acid (be it the sole component of refluxate or not) still remains a major causative factor. A better and more predictable form of acid suppression should therefore be pursued.     

Concomitant irritable bowel syndrome is associated with failure of step‐down on‐demand proton pump inhibitor treatment in patients with gastro‐esophageal reflux disease

Background The predictors for treatment failure of on‐demand proton pump inhibitor (PPI) therapy in gastro‐esophageal reflux disease (GERD) patients are unclear. We studied the efficacy and predictors for treatment failure of step‐down on‐demand PPI therapy in patients with non‐erosive reflux disease (NERD) and those with low grade erosive esophagitis. Methods Consecutive symptomatic GERD patients who had positive esophageal pH studies and complete symptom resolution with initial treatment of esomeprazole were given step‐down on‐demand esomeprazole for 26 weeks. Patients with esophagitis of Los Angeles (LA) grade C or above and recent use of PPI were excluded. Treatment failure was defined as an inadequate relief of reflux symptoms using global symptom assessment. Potential predictors of treatment failure were determined using multivariate analysis. Key Results One hundred and sixty three NERD and 102 esophagitis patients were studied. The 26‐week probability of treatment failure was 36.2% (95% CI: 23.9–46.5%) in NERD group and 20.1% (95% CI: 10.9–28.3%) in esophagitis group, respectively (P = 0.021). Irritable bowel syndrome (adjusted HR: 2.1, 95% CI: 1.5–3.8, P = 0.01), in addition to daily reflux symptom (adjusted hazard ratio: 2.7, 95% CI: 1.9–4.2, P = 0.001) and concomitant dyspepsia (adjusted hazard ratio: 1.7, 95% CI: 1.1–2.8, P = 0.04), were independent predictors for treatment failure. Conclusions & Inferences Compared to patients with esophagitis, NERD patients have higher failure rate of on‐demand PPI therapy. Concomitant irritable bowel syndrome, in addition to daily reflux symptom and dyspepsia, is associated with the failure of on‐demand PPI in these patients.     

Relationship between baseline impedance levels and esophageal mucosal integrity in children with erosive and non-erosive reflux disease

Background Baseline impedance measurement has been reported to be related to esophageal acid exposure and hypothesized to be a marker of microscopic changes of the esophageal mucosa. Aims of the study were to establish whether any relationship existed between the magnitude of intercellular space diameter (ISD) of esophageal mucosa and baseline impedance levels in children with gastro‐esophageal reflux disease (GERD), and to compare baseline impedance levels between children with non erosive (NERD) and erosive (ERD) reflux disease. Methods Fifteen children (median age: 11.2 years) with NERD, and 11 with ERD (median age: 9.6 years) were prospectively studied. All patients underwent upper endoscopy. Biopsies were taken 2–3 cm above the Z‐line, and ISD was measured using transmission electron microscopy. All patients underwent impedance pH‐monitoring, and baseline impedance levels were assessed in the most distal impedance channel. Key Results Mean (±SD) ISD did not differ between NERD (1.0 ± 0.3 μm) and ERD (1.1 ± 0.3 μm, ns). Considering all patients together, no correlation was found between distal baseline impedance and ISD (r: ?0.15; ns). Conversely, negative correlations were found between distal baseline impedance and acid exposure time (r: ?0.76; P < 0.001), long‐lasting reflux episodes (r: ?0.78; P < 0.001), acid reflux episodes (r: ?0.62; P < 0.001), and acid clearance time (r: ?0.79; P < 0.001). Distal baseline impedance was significantly lower in ERD [1455 (947–2338) Ω] than in NERD children [3065 (2253–3771) Ω; P < 0.01]. Conclusions & Inferences In children with GERD baseline impedance levels are not useful in predicting reflux‐induced ultrastructural changes in the esophageal mucosa, despite their ability to discriminate between NERD and ERD.     

Platelet‐activating factor and distinct chemokines are elevated in mucosal biopsies of erosive compared with non‐erosive reflux disease patients and controls

Background A distinction between symptomatic non‐erosive reflux disease (NERD) and erosive esophagitis (EE) patients is supported by the presence of inflammatory response in the mucosa of EE patients, leading to a damage of mucosal integrity. To explore the underlying mechanism of this difference, we assessed inflammatory mediators in mucosal biopsies from EE and NERD patients and compared them with controls. Methods Nineteen NERD patients, 15 EE patients, and 16 healthy subjects underwent endoscopy after a 3‐week washout from PPI or H₂ antagonists. Biopsies obtained from the distal esophagus were examined by quantitative real‐time polymerase chain reaction (qPCR) and multiplex enzyme‐linked immunosorbent assay for selected chemokines and lyso‐PAF acetyltransferase (LysoPAF‐AT), the enzyme responsible for production of platelet‐activating factor (PAF). Key Results Expression of LysoPAF‐AT and multiple chemokines was significantly increased in mucosal biopsies derived from EE patients, when compared with NERD patients and healthy controls. Upregulated chemokines included interleukin 8, eotaxin‐1, ‐2, and ‐3, macrophage inflammatory protein‐1α (MIP‐1α), and monocyte chemoattractant protein‐1 (MCP‐1). LysoPAF‐AT and the chemokine profile in NERD patients were comparable with healthy controls. Conclusions & Inferences Levels of selected cytokines and Lyso‐PAF AT were significantly higher in the esophageal mucosa of EE patients compared with NERD and control patients. This difference may explain the distinct inflammatory response occurring in EE patients’ mucosa. In contrast, as no significant differences existed between the levels of all mediators in NERD and control subjects, an inflammatory response does not appear to play a major role in the pathogenesis of the abnormalities found in NERD patients.     

PPI therapy is equally effective in well-defined non-erosive reflux disease and in reflux esophagitis: a meta-analysis

Background Symptomatic response to proton pump inhibitor (PPI) therapy in patients with non‐erosive reflux disease (NERD) is often reported as lower than in patients with erosive reflux disease (ERD). However, the definition of NERD differs across clinical trials. This meta‐analysis aims to estimate the rate of symptom relief in response to PPI in NERD patients. Methods MEDLINE (1966–2010), Cochrane Comprehensive Trial Register (1997–2010) and EMBASE (1985–2010) databases were searched and manual searches from studies’ references were performed. Randomized clinical trials were selected that included patients with heartburn, and analyzed the effect of short‐term PPI treatment. The primary outcome of selected studies was defined as complete or partial heartburn relief. Two reviewers independently extracted data and assessed study quality of selected articles. Random effects models and meta‐regression were used to combine and analyze results. Key Results The pooled estimate of complete relief of heartburn after 4 weeks of PPI therapy in patients with ERD was 0.72 (95% CI 0.69–0.74) (32 studies), vs 0.50 (0.43–0.57) (eight studies) in empirically treated patients, 0.49 (0.44–0.55) (12 studies) in patients defined as non‐erosive by negative endoscopy, and 0.73 (0.69–0.77) (two studies) in patients defined as non‐erosive by both negative endoscopy and a positive pH‐test. Conclusions & Inferences In well‐defined NERD patients, the estimated complete symptom response rate after PPI therapy is comparable to the response rate in patients with ERD. The previously reported low response rate in studies with patients classified as NERD is likely the result of inclusion of patients with upper gastrointestinal symptoms that do not have reflux disease.     

Measurement of acid exposure of proximal esophagus: a better tool for diagnosing non‐erosive reflux disease

Background The sensitivity of 24‐h pH monitoring is poor in non‐erosive reflux disease (NERD). In NERD patients, the proximal extent of acid reflux is one of the main determinants of reflux perception. The present study was aimed to compare the diagnostic accuracy of acid exposure time (AET), at 5 cm above the lower esophageal sphincter, with those at 10 cm and at 3 cm below the upper esophageal sphincter as well as the reproducibility of these parameters. Methods A total of 93 consecutive NERD patients, with typical symptoms responsive to proton pump inhibitor treatment, and 40 controls underwent esophageal manometry and multi‐channel 24‐h pH‐test; 13 patients underwent the same study on two occasions. Symptom association probability (SAP) values were evaluated at each esophageal level. Key Results The ROC curve indicates that the area under the curve was 0.79 at distal (SE = 0.039), 0.87 (SE = 0.032) at proximal (P = 0.029 vs distal), and 0.85 (SE = 0.033) at very proximal esophagus (P = 0.148). AET showed a reproducibility of 61% (Kappa 0.22) at distal esophagus, 77% (Kappa 0.45) at proximal and 53% (Kappa 0.05) at very proximal esophagus. The percentage of patients with a positive SAP was not significantly different when assessed at the distal compared with the proximal esophagus. Conclusions & Inferences In NERD patients, the diagnostic yield of the pH test is significantly improved by the assessment of AET at the proximal esophagus. As this variable seems to be less affected by the day to day variability, it could be considered a reliable and useful diagnostic tool in NERD patients.     

Failure to respond to physiologic challenge characterizes esophageal motility in erosive gastro‐esophageal reflux disease

Background Non‐specific esophageal dysmotility with impaired clearance is often present in patients with gastro‐esophageal reflux disease (GERD), especially those with erosive disease; however the physio‐mechanic basis of esophageal dysfunction is not well defined. Methods Retrospective assessment of patients with erosive reflux disease (ERD; n = 20) and endoscopy negative reflux disease (ENRD; n = 20) with pathologic acid exposure on pH studies (>4.2% time/24 h) and also healthy controls (n = 20) studied by high resolution manometry. Esophageal motility in response to liquid and solid bolus swallows and multiple water swallows (MWS) was analyzed. Peristaltic dysfunction was defined as failed peristalsis, spasm, weak or poorly coordinated esophageal contraction (>3 cm break in 30 mmHg isocontour). Key Results Peristaltic dysfunction was present in 33% of water swallows in controls, 56% ENRD and 76% ERD respectively (P < 0.023 vs controls, P = 0.185 vs ENRD). The proportion of effective peristaltic contractions improved with solid compared to liquid bolus in controls (18%vs 33%, P = 0.082) and ENRD (22%vs 54%, P = 0.046) but not ERD (62%vs 76%, P = 0.438). Similarly, MWS was followed by effective peristalsis in 83% of controls and 70% ENRD but only 30% ERD patients (P < 0.017 vs controls and P < 0.031 vs ENRD). The association between acid exposure and dysmotility was closer for solid than liquid swallows (r = 0.52 vs 0.27). Conclusions & Inferences Peristaltic dysfunction is common in GERD. ERD patients are characterized by a failure to respond to the physiologic challenge of solid bolus and MWS that is likely also to impair clearance following reflux events and increase exposure to gastric refluxate.     

Diagnosis of supra‐esophageal gastric reflux: correlation of oropharyngeal pH with esophageal impedance monitoring for gastro‐esophageal reflux

Background Oropharyngeal (OP) pH monitoring has been developed as a new way to diagnose supra‐esophageal gastric reflux (SEGR), but has not been well validated. Our aim was to determine the correlation between OP pH and gastro‐esophageal reflux (GER) events detected by multichannel intraluminal impedance‐pH (MII‐pH). Methods Fifteen patients (11 males, median age 10.8 years) with suspected GER were prospectively evaluated with ambulatory 24‐h OP pH monitoring (positioned at the level of the uvula) and concomitant esophageal MII‐pH monitoring. Potential OP events were identified by the conventional pH threshold of <4 and by the following alternative criteria: (i) relative pH drop >10% from 15‐min baseline and (ii) absolute pH drop below thresholds of <5.5, 5.0, and 4.5. The 2‐min window preceding each OP event was analyzed for correlation with an episode of GER detected by MII‐pH. Key Results A total of 926 GER events were detected by MII‐pH. Application of alternative pH criteria increased the identification of potential OP pH events; however, a higher proportion of OP events had no temporal correlation with GER (45–81%), compared with the conventional definition of pH < 4 (40%). A total of 306 full‐column acid reflux episodes were detected by MII‐pH, of which 10 (3.3%) were also identified by OP pH monitoring. Conclusions & Inferences Use of extended pH criteria increased the detection of potential SEGR events, but the majority of decreases in OP pH were not temporally correlated with GER. Oropharyngeal pH monitoring without concurrent esophageal measurements may overestimate the presence of SEGR in children.     

The frequency of apneas in very preterm infants is increased after non‐acid gastro‐esophageal reflux

Background To evaluate whether physical and/or chemical features of gastro‐esophageal reflux (GER) influence its relationship with apnea of prematurity (AOP). Methods Fifty‐eight preterm newborns (GA ≤33 weeks) with recurrent apneas were studied by simultaneous polysomnography and combined impedance and pH monitoring, to analyze whether the correlation between GER and AOP varies according to the acidity, duration and height of GERs. Key Results The frequency of apnea (number apnea/min) occurring after‐GER [median (range) 0.07 (0–0.25)] was higher than the one detected in GER‐free period [0.06 (0.04–0.13), P = 0.015], and also than the one detected before‐GER [0 (0–0.8), P = 0.000]. The frequency of apneas detected in the 30’’ after pH‐GER [median (range), 0 min^?1 (0–1.09)] was higher than the frequency detected in the 30’’ before [0 (0–0.91), P = 0.04]; even more, the frequency of apneas detected after non‐acid MII‐GER episodes [0 (0–2)] was significantly higher than the one detected before [0 (0–1), P = 0.000], whereas the frequency of apneas detected before acid MII‐GER episodes [0 (0–0.67)] did not differ from the one detected after [0 (0–2), P = 0.137]. The frequency of pathological apneas detected in the 30’’ after‐GER (0 min^?1, range 0–0.55) was higher than the frequency detected before (0, range 0–0.09; P = 0.001). No difference in mean height or in mean duration was found between GERs correlated and those non‐correlated to apnea. Conclusions & Inferences Non‐acid GER is responsible for a variable amount of AOP detected after‐GER: this novel finding must be taken into consideration when a therapeutic strategy for this common problem is planned.     

Treatment of gastro‐esophageal reflux disease: the new kids to block

Refractory gastro‐esophageal reflux disease (GERD), defined as persistent symptoms despite proton pump inhibitor (PPI) therapy, is an increasingly prevalent condition and is becoming a major challenge for the clinician. Since non‐acidic reflux may be associated with symptoms persisting during PPI treatment, the lower esophageal sphincter (LES), the most important barrier protecting against reflux, has become an important target for the treatment of (refractory) GERD. Preclinical research has identified several receptors that are involved in the control of transient lower esophageal sphincter relaxations (TLESRs), the predominant mechanism of both acid and non‐acidic reflux events, and several drugs have now been tested in humans. The GABA_B agonist baclofen has demonstrated to effectively reduce the rate of TLESRs and the amount of reflux in both GERD patients and healthy volunteers. Nevertheless, the occurrence of central side effects limits its clinical use for the treatment of GERD. Several analogues are being developed to overcome this limitation and have shown promising results. Additionally, metabotropic glutamate receptor 5 (mGluR5) receptor antagonists have shown to reduce both acid and non‐acidic reflux in GERD patients and several molecules are currently being evaluated. Although CB₁ antagonists have been shown to reduce TLESRs, they are also associated with central side effects, limiting their clinical applicability. Despite the identification of several potentially interesting drugs, the main challenge for the future remains the reduction of central side effects. Moreover, future studies will need to demonstrate the efficacy of these treatments in patients with refractory GERD.     

The added value of quantitative analysis of on-therapy impedance-pH parameters in distinguishing refractory non-erosive reflux disease from functional heartburn

Background By analysis of symptom‐reflux association, endoscopy‐negative refractory heartburn can be related to acid/non‐acid refluxes with impedance‐pH monitoring. Unfortunately, patients frequently do not report symptoms during the test. We aimed to assess the contribution of quantitative analysis of impedance‐pH parameters added to symptom‐reflux association in evaluating patients with endoscopy‐negative heartburn refractory to high‐dose proton pump inhibitor therapy. Methods The symptom association probability (SAP), the symptom index (SI), the esophageal acid exposure time and the number of distal and proximal refluxes were assessed at on‐therapy impedance‐pH monitoring. Relationships with hiatal hernia and manometric findings were also evaluated. Key Results Eighty patients were prospectively studied. Refractory heartburn was more frequently related to reflux by a positive SAP/SI and/or abnormal impedance‐pH parameters (52/80 cases) (65%) than by a positive SAP/SI only (38/80 cases) (47%) (P = 0.038). In patients with refractory non‐erosive reflux disease (NERD) defined by a positive SAP/SI and/or abnormal impedance‐pH parameters, the prevalence of hiatal hernia was significantly higher (56%vs 21%, P = 0.007) and the mean lower esophageal sphincter tone was significantly lower (18.7 vs 25.8 mmHg, P = 0.005) than in those (35%) with reflux‐unrelated, i.e., functional heartburn (FH). On the contrary, no significant difference was observed subdividing patients according to a positive SAP/SI only. Conclusions & Inferences Quantitative analysis of impedance‐pH parameters added to symptom‐reflux association allows a subdivision of refractory‐heartburn patients into refractory NERD and FH which is substantiated by pathophysiological findings and which restricts the diagnosis of FH to one third of cases.