**2. Material and Methods**

### *2.1. Study Design and Setting*

A case-control study design was adopted in the department of endoscopy at a central hospital (King Khalid) which received all medical referrals in Najran region southwest of Saudi Arabia.

### *2.2. Subjects' Recruitment and Inclusion and Exclusion Criteria*

A consecutive test group consisted of 340 obese patients; defined with a BMI of ≥30 kg/m<sup>2</sup> with a serious comorbidity (e.g., diabetes mellitus, ischemic heart disease, obstructive sleep apnea) or with a BMI of ≥40 [27] who had undergone diagnostic upper endoscopy before sleeve gastrectomy were enrolled into the study over the period between January 2013–December 2014. Over the same

period, a similar number of 340 patients; with BMI of <30 kg/m<sup>2</sup> who had undergone diagnostic upper endoscopy in the same hospital and department due to other reasons and complain (e.g., epigastric pain and dyspepsia) were selected as controls with approximately 1:1 ratio test to control. Both groups self-reported neither tested nor treated for *H. Pylori* in the past 5 years.

We excluded patients with advanced liver disease, malignancy, renal failure, those taking bismuth subcitrate, history of taking eradication therapy of HPPI within six months, with acute infection and, gastro intestinal bleeding or patients with history of proton pump inhibitor (PPI) or antibiotics intake 2 weeks before the endoscopic procedure as these are known to may lead to false negative results for HPPI test.

### *2.3. Variables and Clinical Procedures*

The data for both groups included the demographics (age, gender), medication use, laboratory results (e.g., CBC, coagulation profile, RFT, LFT, Cortisol, TFT, blood sugar, lipid profile), endoscopic and histologic finding (e.g., Gastritis, PUD, GERD, Hiatus Hernia). All patients underwent the endoscopic procedure with standard technique (using Olympus GF260, 9.6 mm diameter scope) to assess for HPPI test. Patient were lying in the left lateral position with a mouth piece placed and their throat sprayed with adequate xylocaine. Two antral biopsies were taken from antrum and lower body for each patient, as per the routine practice of the endoscopy unit, and submitted for histologic evaluation. No complication related to endoscopy was reported in any subject. The specimens were stained by hematoxylin and eosin stain or methylene blue. The laboratory investigator was blinded to the sample status to avoid bias.

Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2). BMI greater than or equal to 25 is considered to be overweight, and BMI greater than or equal to 30 is considered to be obesity [28]. As for body mass index a digital scale was used to measure the weight of patient to the nearest 0.1 kg and height was considered in a standing position without shoes and in light clothing.
