Prevalence of Asymptomatic Hiatal Hernia in Obese Patient in Routine Upper Gastrointestinal Endoscopy Screening and Correlation with BMI

Background In obese patients, hiatus hernia (HH) can be asymptomatic or it may present with one or few symptoms such as heartburn, nausea, or vomiting. Routine upper gastrointestinal endoscopy is the most frequent method to determine the presence of any abnormalities including hiatus hernia. The aim of this study is to assess the prevalence of asymptomatic hiatal hernia in obese patients in routine upper GI endoscopy assessment and correlation with BMI. Methods This was an observational retrospective cohort study conducted at King Fahad Specialist hospital - Buraydah, Qassim, Saudi Arabia. The data were extracted from the medical records and electronic charts of all obese patients who had preoperative upper gastrointestinal endoscopy assessment between January 2017 – December 2019. Data were tabulated in Microsoft Excel and were analyzed using SPSS version 21. Results Among the 690 obese patients, the prevalence of HH was 103 yielding an overall percentage of 14.9%. Chi-square test revealed that the abdominal pain (X2=3.885; p=0.049), shortness of breath (X2=8.057; p=0.005), vomiting (X2=4.302; p=0.038), nausea (X2=4.090; p=0.043) and other HH symptoms (X2=3.897; p=0.048) signicantly inuenced HH but the BMI level did not (X2=2.126; p=0.345). In multivariate regression model, the use of PPI medication (AOR=0.237; CI=0.074 – 0.760; p=0.023), while vomiting (AOR=1.722; CI=1.025 – 2.890; p=0.040) and nausea (AOR=1.698; CI=1.012 – 2.849; p=0.045) signicantly increased the risk of HH. Conclusion Asymptomatic HH among obese patients is not widely prevalent in our region.


Introduction
Obesity can affect one's health in many ways including hiatal hernia, i.e., dilation in the diaphragmatic opening through which the esophagus passes. This dilation can cause part or the whole stomach to migrate into the thoracic cavity (1). A prospective study included 1224 participants who were sent for upper gastrointestinal endoscopy and found that 65% of patients with increased waist-to-hip (W/R) ratio present with esophagitis or hiatal hernia (2). Patients with hiatal hernia or esophagitis can show no or few symptoms. It can be found incidentally while investigating digestive disorders using upper gastrointestinal tract endoscopy (3).
Hiatal Hernia is classi ed as sliding hiatal hernia. This type is the most common type (95% of patients); para-esophageal hiatal hernia is seen when the lower esophageal sphincter remains preserved while the fundus of the stomach herniates through the diaphragm. There is also a mixed type. The fourth type involves the migration of stomach or bowel. The common symptoms of this disease include dysphagia, heartburn, regurgitation, nausea/vomiting, chest pain, or abdominal pain (4). There are multiple risk factors associated with hiatal hernias including age, gender, race, BMI, or any increase in the intraabdominal pressure (1). Hiatal hernia can be detected using multiple studies. However, only two studies can accurately diagnose hiatal hernia including barium swallow and upper endoscopy (4).
Looking at variations in the incidence and frequency among obese patients and the correlation with asymptomatic hiatal hernia between studies-and considering that the prevalence of asymptomatic hiatal hernia in Al'Qassim province in Saudi Arabia has not been yet established-we conducted a retrospective study on this topic. We then compared the results with other studies conducted inside and outside Saudi Arabia to fully understand the prevalence. The aim of this study was to determine the prevalence of asymptomatic HH in obese patients in routine upper GI endoscopy screening and to assess the relation between BMI and the presence of hiatal hernia.

Materials And Methods
An observational retrospective cohort study was conducted at King Fahad Specialist hospital -Buraydah, Qualitative data were expressed as frequencies and percentages. Quantitative data were expressed as mean and standard deviation. The relationship between hiatal hernia among the basic demographic characteristics and associated diseases of obese patients was established using a Chi square test. A non-parametric test was used for non-normally distributed variables, and the variables were expressed as the median and interquartile range. A multivariate regression analysis was also conducted to determine the independent signi cant factor associated with HH where the adjusted ratio as well as 95% con dence interval were also reported. A p-value of <0.05 was considered statistically signi cant. All statistical analyses were performed using Statistical Packages for Software Sciences (SPSS) version 21 Armonk, New York, IBM Corporation, USA. The data from a total of 690 obese patients who had upper gastrointestinal screening from January 2017 to December 2019 were analyzed. Table 1 presents the basic demographic characteristics of our patients. The range of patients' age was from 15 to 63 years old (mean: 33.9) with 26 -35 years being the most common age group (33.9%). Females were slightly more prevalent (57.1%) than women (42.9%). Furthermore, nearly all patients were Saudis (99.4%). More than half of them (54.1%) were classi ed as morbidly obese. In addition, only 1.7% were using PPI medications. Figure 1 shows the prevalence of HH among obese patients. The prevalence of HH among obese patients was 14.9% while the majority were negative from HH (85.1%).

Result
In gure 2, the most commonly known symptom related to HH was nausea (15.7%) followed by vomiting and abdominal pain (both 15.5%, each respectively) while shortness of breath was the least frequent complaint (0.7%). Figure 3 presents chronic diseases associated with obese patients. The most frequently cited chronic disease was diabetes (14.3%) followed by hypothyroidism (9.1%) and nally hypertension and asthma (both at 7% each, respectively).

Discussion
Hiatus hernia is a stomach disorder that involves herniation of the contents of the abdominal cavity. In United States, reports between 2003 and 2006 indicated that HH was the primary and secondary cause of hospitalization in 142 of 10,000 inpatients (5). However, the exact prevalence of HH is di cult to ascertain due to the inherent subjectivity of diagnostic criteria. In this study, we sought to determine the prevalence of asymptomatic HH among obese patients and evaluate whether it has any link to BMI level.
The prevalence of asymptomatic HH in this study was low (14.9%). Several papers have documented the prevalence of HH among obese patients or patients with gastrointestinal problems ranging from 9.3% to 37% (2, 6-10). Che et al. (6) recorded the highest prevalence of HH (37%) while Hyun et al. (7), recorded a very low prevalence (9.3%). The prevalence of HH in this study was consistent from the paper of Petersen et al. (8) who reported a prevalence of 17% among patients with gastroesophageal re ux symptoms.
Age and obesity are the most commonly known risk factors of HH (10)(11)(12). Compared to people with normal body weight, overweight or obese people had a progressive increase in intra-abdominal pressure, which leads to herniation (13). Wilson and Hirschowitz found that the presence of HH was signi cantly associated with excessive body weight and the probability of HH increased with each level of BMI (14). This has been validated in a meta-analysis conducted by Menon and Trudgill (15) who observed that the odds ratio for HH in people with a BMI greater than 25 was 1.93 (95% con dence interval 1.10 to 3.39) with risk increasing as the BMI increased. However, in our study, we failed to prove the correlation between BMI and HH (X2=2.126; p=0.345); age was not a signi cant predictor in contrast to previous results.
Further analysis univariate determined that the use of PPI medication as well as abdominal pain, shortness of breath, vomiting, nausea, and other symptoms of HH signi cantly in uenced HH. However, after conducting multivariate regression estimates, we found that the use of PPI medication signi cantly decreased the presence of HH while vomiting and nausea signi cantly increased the risk of HH. This indicates that the use of PPI was likely a protective factor of HH whereas vomiting and nausea are the signi cant risk factors associated with HH. Other reports discussed gender and HH and found that males were more frequently diagnosed with HH than females (6,15). In our paper, the relationship between gender did not differ signi cantly with HH in contrast to previous results.
Moreover, this study suggests that no speci c symptoms are attributed to HH. Symptoms related to gastroesophageal re ux including heartburn, regurgitation, or dysphagia were linked to HH due to the occurrence of hernia (16). In our study, the most common symptoms related to HH were nausea (15.7%) followed by vomiting and abdominal pain (each 15.5%); shortness of breath was the least common symptom (0.7%) which is not similar to previous ndings.

Conclusion
Asymptomatic HH among obese patients is not common in Saudi Arabia. The use of PPI medications is a protective factor of HH while symptoms such as vomiting and nausea increased the risk of HH. On the other hand, there was no evidence linking BMI to HH as shown in this study. More research is needed the validate the prevalence of asymptomatic HH associated with obese patients in our region. Symptoms related to hiatal hernia. Chronic diseases of the obese patients.