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Supragastric Belching And Acid Reflux Severity

Supragastric Belching And Acid Reflux Severity

SGB, known as supragastric belching, is a behavioral disorder where individuals rapidly inhale and expel air. It is commonly observed in those experiencing symptoms resembling acid reflux, as well as in individuals with excessive belching. Studies in the past have indicated a higher prevalence of esophageal hypomotility and increased acid exposure in certain SGB patients.


To further investigate the impact of supragastric belching on motility, reflux, and acid exposure, a large cohort of 348 SGB patients was studied. Common symptoms included heartburn, belching, and regurgitation. Among the patients, 27% were diagnosed with ineffective esophageal motility (IEM). Supragastric belching was associated with 47% of all reflux events and 53.6% of acid reflux events, accounting for 27.3% of acid publicity time (APT). Severe SGB correlated with even higher percentages—62% of acid reflux events and 46% of AET were linked to severe SGB.


The study concludes that SGB is prevalent and significantly related to IEM, contributing to nearly one-third of esophageal acid burden. The impact of supragastric belching corresponds to the level of its severity. Therefore, it is essential to consider a diagnosis of SGB in patients with excessive belching or persistent reflux symptoms. Behavioral therapy aimed at managing SGB may alleviate acid exposure and enhance patients’ quality of life.



The act of belching involves the audible release of air from either the esophagus or the stomach into the pharynx. As per the Rome IV criteria, this becomes a clinically relevant disorder when it interferes with regular activities for more than three days a week. There are two types of belching distinguishable by impedance-pH monitoring: gastric belching, a natural mechanism to expel excess gas after meals, and supragastric belching, where air is rapidly sucked from the mouth and pharynx into the esophagus, followed by expulsion through abdominal straining.


Supragastric belching might start as a voluntary response to abdominal or thoracic discomfort but can become involuntary over time, impacting patients’ health-related quality of life, social functioning, and mental health when excessive (over 13 events in a 24-hour period). Belching disorders were found in about 1% of the surveyed global population, and SGB is increasingly diagnosed in patients with refractory reflux-like symptoms, esophageal hypersensitivity, or postprandial regurgitation. The relationship between SGB and reflux events has been described, suggesting that SGB might provoke reflux in certain cases. Some studies reported an increased prevalence of esophageal hypomotility and increased acid exposure in SGB patients, with a subgroup experiencing SGB-driven acid reflux.


Recognizing and diagnosing SGB is crucial since it is unlikely to respond to conventional reflux therapy. Treatment options include cognitive behavioral therapy (CBT) and speech therapies, with CBT showing effectiveness in reducing SGB frequency and improving social and daily activities. The largest cohort study included 100 SGB patients.


The unit conducting the research has become a referral center for belching and refractory reflux patients. They aimed to assess the prevalence, severity, and impact of SGB on esophageal function and symptoms in a large cohort of SGB patients, hypothesizing that SGB has a significant impact on motility and acid exposure that increases with its severity.



Inclusion Criteria

– Patients with a diagnosis of pathological supragastric belching based on impedance-pH reflux monitoring (MII-pH) between the years 2011 and 2021.

– Data obtained from the computerized database of the Upper Gastro-intestinal (GI) Physiology unit in the Royal London Hospital.

– Referral for MII-pH monitoring was made at the discretion of a treating doctor.

– Patients referred for MII-pH monitoring due to various reasons.


Exclusion Criteria

– Patients with incomplete or technically inadequate MII-pH examination.

– Patients on proton pump inhibitors (PPI) therapy were excluded.

– Pediatric patients were not included in the study.

– Patients with a history of systemic neurologic disorders.

– Patients with a history of gastric or esophageal surgery.

– Patients with major motility disorders such as achalasia.


Demographic, clinical, motility, and reflux-related data were collected from eligible patients. The initial search in the database yielded 409 patients with a diagnosis of SGB among the 8708 patients referred for reflux monitoring. After applying the inclusion and exclusion criteria, a total of 348 patients were considered for further analysis.


The study was conducted as part of an audit of upper gastrointestinal physiology clinical studies at the Royal London Hospital and received approval from the Quality and Service Improvement department.


Statistical Analysis

In this study, impedance studies were re-evaluated in the selected patients to identify supragastric belching events. Since no existing software can detect SGB, a manual review of all readings was conducted. The MIIpH studies were carried out using either Sandhill® (Diversatek Healthcare) or AlpHaLAB® (Jinshan Science & Technology Ltd) systems. An SGB event was confirmed when a pattern of antegrade air movement, characterized by a rapid impedance rise (≥1000 Ω) immediately followed by retrograde air movement, was observed in all, or all but one, of the impedance channels.


Pathologic supragastric belching was defined by the presence of more than 13 SGB events in a 24-hour period. The SGB patients were further categorized into mild (13-50 events), moderate (51-100 events), or severe (>100 events) based on the number of SGB events per day. Reflux events occurring within 5 seconds of SGB were considered SGB-related. SGB-related acid exposure was calculated as the proportion of the total duration of acid reflux events caused by SGB compared to the overall duration of acid reflux.


If high-resolution manometry was performed during the same visit as the impedance study, it was included in the analysis. The presence of adequate contractile reserve was defined by a ratio of multiple rapid swallows distal contractile integral (DCI) to mean single swallow DCI greater than 1.


In the analysis, continuous variables such as acid exposure time (AET) were presented as the mean and standard deviation if they followed a normal distribution, and as the median and interquartile range (IQR) if the data was not normally distributed, for instance, the number of reflux events. Categorical variables, such as symptoms, were reported as the number and proportion of occurrences.


To compare groups, either Student’s t-test or the Mann-Whitney test was utilized for continuous variables, while the Pearson chi-squared test was employed for proportions. A significance level of p-values <0.05 was considered statistically significant, indicating meaningful differences between the groups.



Among the patients included in the study, both high-resolution manometry and impedance-pH (MIIpH) data were available for 318 individuals, while an additional 30 patients had only MIIpH data. The median age of the participants was 48 years old, with a range of 37 to 59 years. Of the total patients, 41% (n = 144) were male. Self-reported ethnicity revealed that 51% of the patients identified as White.


Supragastric belching and symptoms

In our study cohort, heartburn (25.4%) and belching (23.4%) emerged as the most common main symptoms, followed by regurgitation (13%). A significant portion of patients (24.5%) experienced atypical gastroesophageal reflux disease (GERD) symptoms, such as cough, bloating, globus, and sore throat. Dysphagia was the primary symptom for 4.9% of patients, while 36.6% reported some degree of dysphagia when specifically asked. Apart from vomiting, which was significantly more common in females (9/202 vs. 1/144, p = 0.04), there were no gender-based differences in supragastric belching presenting symptoms.


Regarding supragastric belching severity, 14.6% (n = 51) of patients had mild SGB, 33.6% (n = 117) had moderate SGB, and the majority, 51.7% (n = 180), experienced severe SGB.


Supragastric belching and reflux

As a whole, patients with supragastric belching exhibited elevated esophageal acid exposure, with a mean acid exposure time (AET) of 5.4%. During the examination period, they experienced a median of 46 reflux events, out of which 20 were acid events. Individuals with reflux-like symptoms had a comparable number of total reflux events to those with non-reflux symptoms (50 vs. 43, p = not significant), but they had significantly higher numbers of acid reflux events (31 vs. 24, p = 0.017), resulting in higher AET (6.6% vs. 5.1%, p = 0.03).


Approximately 47% of all reflux events, 42% of non-acid reflux events, and 53.6% of acid reflux events were attributed to supragastric belching. The impact of SGB on acid exposure was particularly notable in severe SGB cases. Esophageal acid exposure associated with SGB-related acid reflux episodes accounted for 27.3% of total acid exposure.


Supragastric belching severity demonstrated a significant influence on both AET and reflux events. Those with mild SGB had an AET of 3.7% compared to 6.3% in those with severe SGB (p = 0.01), with the proportion of AET attributed to SGB increasing accordingly. Similarly, the number of reflux and acid reflux events was higher in severe SGB compared to mild SGB, with the proportion of acid reflux events due to SGB increasing in the severe SGB group.


The proportion of patients with GERD defined by AET >6 increased from 19.6% in the mild SGB cohort to 37% in those with severe SGB (p = 0.018). Hiatal hernia was found in 23.5% of patients and was associated with increased AET compared to those without a hernia. However, the presence of hiatal hernia was not linked to an increased prevalence of ineffective esophageal motility (IEM) or increased SGB severity.


According to the Chicago 4 classification for esophageal motor disorders, 73% (n = 232) of the patients exhibited normal esophageal motility, while 27% (n = 86) were diagnosed with ineffective esophageal motility (IEM). Among those with IEM, 47.5% (n = 38) demonstrated adequate contractile reserve after the multiple rapid swallows test.


The prevalence of IEM showed a trend of increasing with supragastric belching severity, with rates of 23.4% in mild, 24.9% in moderate, and 29.6% in severe SGB cases, although this difference did not reach statistical significance. Additionally, there was no significant difference in acid exposure time (AET) between patients with normal esophageal motility and those with IEM (6.2 vs. 5.2, p = 0.17).



In patients undergoing upper GI studies, supragastric belching is frequently encountered and presents itself through typical and atypical esophageal symptoms. This behavior contributes substantially, accounting for nearly one-third of the esophageal acid burden and showing an association with a higher incidence of ineffective esophageal motility (IEM). The impact of SGB on acid exposure is directly related to its severity. It is crucial to actively seek a diagnosis of supragastric belching, particularly in patients with excessive belching, refractory reflux, or IEM in the absence of significant gastroesophageal reflux disease (GERD). The development of automated software to detect and quantify supragastric belching is necessary for accurate patient identification. By recognizing and addressing SGB in patients, acid exposure can be alleviated, potentially leading to an improved quality of life.

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