Prevalence of Asymptomatic Hiatal Hernia in Obese Patients During Preoperative Upper Gastrointestinal Endoscopy Assessments and Correlation With Body Mass Index

Introduction In obese patients, hiatal hernia (HH) can be asymptomatic or may present with one or few symptoms, such as heartburn, nausea, or vomiting. Routine upper gastrointestinal (GI) endoscopy is the most frequent method used to determine the presence of any abnormalities, including HH. This study aimed to assess the prevalence of asymptomatic HH in obese patients during routine upper GI endoscopy assessments and to examine the correlation with body mass index (BMI). Materials and 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 underwent preoperative upper GI endoscopy assessment between January 2017 and December 2019. Data were tabulated in Microsoft Excel and analyzed using the Statistical Package for the Social Sciences (SPSS) Version 21 (IBM Corp., Armonk, NY, USA). Results Among the 690 obese patients, HH was found in 103 (14.9%) patients. The chi-square test revealed that 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) were the most frequently reported HH related symptoms, but BMI was not (X2=2.126; p=0.345). In the multivariate regression model, the use of PPI (proton-pump inhibitor) medication (adjusted OR [AOR]=0.237; 95% CI=0.074-0.760; p=0.023) was found to be higher in those with HH. Vomiting (AOR=1.722; 95% CI=1.025-2.890; p=0.040) and nausea (AOR=1.698; 95% CI=1.012-2.849; p=0.045) were the most frequently reported symptoms related to HH. Conclusion Asymptomatic HH among obese patients is not widely prevalent in our region. The use of PPI medications was found to decrease the symptoms associated with HH, such as vomiting and nausea. However, there was no evidence linking BMI to the development of HH.


Introduction
Obesity can affect one's health in many ways, including the incidence of hiatal hernia (HH), that is, dilation or weakness of the diaphragmatic opening through which the esophagus passes. This dilation can cause a part or the entirety of the stomach to migrate into the thoracic cavity [1]. A prospective study conducted in the University of Alabama at Birmingham Hospital, Birmingham, AL, USA, included 1,224 participants who underwent upper gastrointestinal (GI) endoscopy and found that 65% of patients with an increased waist-tohip ratio presented with esophagitis or HH [2]. Patients with HH or esophagitis can present with few or no symptoms. It can be found incidentally while investigating digestive disorders using upper GI tract endoscopy [3].
According to Hill's classification, HH is classified based on endoscopic findings into the following: sliding HH, which is the most common type (95% of patients); para-esophageal HH, which is seen when the lower esophageal sphincter remains preserved while the fundus of the stomach herniates through the diaphragm; mixed type; and the fourth type, which involves migration of the stomach or bowel. The common symptoms of this disease include dysphagia, heartburn, regurgitation, nausea/vomiting, chest pain, and abdominal pain [4,5]. There are multiple risk factors associated with HHs, including age, sex, race, body mass index (BMI), or any increase in intra-abdominal pressure [1]. HHs can be detected with multiple techniques. However, only two techniques can accurately diagnose HHs: barium swallow and upper endoscopy [4].
Considering the variations in the incidence and frequency of HH among obese patients and the correlation with asymptomatic HH between studies and considering that the prevalence of asymptomatic HH in the Al-Qassim province in Saudi Arabia has not yet been established, we conducted a retrospective study on this topic. We then compared the results with those of other studies conducted in and outside Saudi Arabia to fully understand its prevalence. This study aimed to determine the prevalence of asymptomatic HH in obese patients during routine upper GI endoscopy preoperative assessment and to assess the relationship between BMI and the presence of HH. This article was previously posted to the Research Square preprint server on October 23, 2020 [6].

Materials And Methods
An observational retrospective cohort study was conducted at King Fahad Specialist Hospital, Buraydah, Qassim, Saudi Arabia. The study was approved by the Institutional Review Board of the National Bioethics Committee in the Qassim province. The data were extracted from the medical records and ambulatory records of all obese patients (BMI > 30) who underwent preoperative upper GI endoscopy assessment between January 2017 and December 2019. Demographic, clinical, and endoscopic data were collected from electronic health records.
Qualitative data were expressed as frequencies and percentages, and quantitative data were expressed as the mean and standard deviation. The relationship between HH and 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 medians and interquartile ranges. A multivariate regression analysis was also performed to determine the independent significant factors associated with HH, where the adjusted ratio and 95% confidence interval were also reported. A pvalue of <0.05 was considered statistically significant. All statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS) Version 21 (IBM Corp., Armonk, NY, USA).

Results
Data of 690 obese patients who underwent preoperative upper GI assessment between January 2017 and December 2019 were analyzed.   Figure 1 shows the prevalence of HH in obese patients. The prevalence of HH among obese patients was 14.9% (103), of whom 67% (69) were asymptomatic. 2021 Figure 2 presents chronic diseases associated with obese patients. The most frequently cited chronic disease was diabetes mellitus (14.3%) followed by hypothyroidism (9.1%), hypertension (7%), and asthma (7%).

FIGURE 2: Chronic diseases in obese patients
In Table 3

Discussion
HH is a stomach disorder that involves herniation of the abdominal cavity. In the United States from 2003 to 2006, HH was the primary and secondary cause of hospitalization in 142 of 10,000 inpatients [5]. However, the exact prevalence of HH is difficult to ascertain owing to the inherent diagnostic criteria. In a study performed in Romania, preoperative investigations such as upper endoscopy and barium swallow X-ray studies are less sensitivity in some cases, which explains that almost half (43.37%) of the patients with HHs were discovered intraoperatively [7]. In this study, we sought to determine the prevalence of asymptomatic HH among obese patients and to evaluate whether it is associated with BMI. The prevalence of asymptomatic HH in this study was low (14.9%). Several studies have documented the prevalence of HH among obese patients or patients with GI problems, ranging from 9.3% to 37% [2,[8][9][10][11][12]. Che et al. [1] reported the highest prevalence of HH (37%), while Hyun et al. [11] reported a very low prevalence (9.3%). The prevalence of HH in this study was consistent with that reported by Petersen et al. [12], who reported a prevalence of 17% among patients with gastroesophageal reflux symptoms.
Age and obesity are the most common risk factors for HH [12][13][14]. Compared to people with normal body weight, overweight or obese people have a progressive increase in intra-abdominal pressure, which leads to herniation [15]. Another study found that the presence of HH was significantly associated with excessive body weight, and the probability of HH increased with each level of BMI [16]. This has been validated in a meta-analysis conducted by Menon and Trudgill [17], who observed that the odds ratio for HH in people with a BMI greater than 25 was 1.93 (95% CI: 1.10-3.39), with the risk increasing as the BMI increased. However, in our study, we failed to prove a correlation between BMI and HH (X2=2.126; p=0.345); age was also not a significant predictor, in contrast to previous results.
Univariate analysis determined that the most frequently reported symptoms of HH were abdominal pain, shortness of breath, vomiting, nausea, and others. However, after performing multivariate regression estimates, we found that the use of PPI medication was found to decrease the symptoms associated with HH. Other reports studied sex and HH and found that males were more frequently diagnosed with HH than females [8,17]. In the present study, the relationship between sex and HH did not differ significantly, in contrast to previous results.
Moreover, this study suggests that no specific symptoms are associated with HH. Symptoms related to gastroesophageal reflux, including heartburn, regurgitation, and dysphagia, were linked to HH due to the occurrence of hernia [18]. In our study, the most common symptoms related to HH were nausea (15.7%) followed by vomiting and abdominal pain (each 15.5%), and shortness of breath was the least common symptom (0.7%), which is not consistent with previous findings.

Conclusions
Asymptomatic HH among obese patients is uncommon in Saudi Arabia. The use of PPI medications was found to decrease the symptoms associated with HH, while symptoms such as vomiting and nausea were the most frequently reported in those with HH. Conversely, there was no evidence linking BMI to the development of HH. More research is needed to validate the prevalence of asymptomatic HH in obese patients in our region.

Additional Information Disclosures
Human subjects: Consent was obtained or waived by all participants in this study. Committee of Bioethics of the General Directorate of Health Affairs, Qassim, Saudi Arabia. issued approval 1441-18088893. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.