The purpose of this study is to investigate whether dexlansoprazole can be as effective as double dose PPI to achieve SSR in high BMI cases with reflux esophagitis in Los Angeles grades A & B.

This study is conducted in National Cheng Kung University Hospital, a tertiary health care center in Tainan, Taiwan. All participants give written informed consent before enrollment. After panendoscopy to confirm enrollment eligibility and reflux esophagitis in Los Angeles A or B, all patients are evenly randomized into a DEX group (receiving 8-week dexlansoprazole 60 mg per day) or double-dose PPI group (receiving 8-week lansoprazole 30 mg twice daily). The enrolled patients are randomized by two series of sealed envelopes containing a prescheduled group code; one series for the overweight patients and the other for the obese patients. In each series of the sealed envelopes, the number of the group code will be equal within every 10 sealed envelopes.

In each patient, the demographic factors and the genotype of S-mephenytoin 4'-hydroxylase (CYP2C19) will be checked and defined as poor metabolizer (PM), homologous (HomoEM) or heterologous extensive metabolizer (HeteroEM). Each patient is treated continuously with dexlansoprazole 60 mg per day or lansoprazole 30 mg twice daily for eight weeks. During this 8-week study period, each patient is requested to record their daily clinical symptoms of reflux esophagitis on a special sheet, including the severity of acid regurgitation (AR, score 0: free from symptoms; score 1: attack episodes < 5 times per day; score 2: 6-10 times per day; score 3: more than 10 episodes per day), heartburn (HB, score 0: absence of symptoms; score 1: tolerable events not interfering with daily work; score 2: intolerable events interfering with daily work, but not needing medication to relieve the symptoms; score 3: complaints interfering with the completion of daily work, or causing the patient to wake up during the night with cough, or combined with any other non-specific complaints). The patients are scheduled to return to clinics for drug refills, and to hand back daily symptom records at the end of the fourth and eighth week of treatment.

The cumulative proportions of patients with sustained symptomatic response (SSR), defined as free from acid regurgitation and heartburn for the last seven days, are recorded during the 8-week study period for each study group. All of the patients starting the treatment are included for the intention-to-treat (ITT) analysis of the rate of SSR. If patients have obvious symptoms despite continuous PPI usage and have an unscheduled visit to load up on additional PPIs during the study, the case is then dropped from the per-protocol (PP) analysis. In addition, patients lost to follow-up are excluded from the PP analysis to determine the rate of SSR. Besides comparing the difference of the rate of SSR between the two study groups, the study also determined whether patients with different CYP2C19 genotypes have differences in the cumulative rates of SSR after therapy between the two study groups.

Inclusion Criteria:

• Eligible participants included patients ≥20 years with either overweight (BMI of 25-30 kg/m2) or obese (BMI > 30 kg/m2), who had undergone panendoscopy due to typical clinical symptoms of either acid regurgitation, heartburn sensation, or both. By the results of panendoscopy, patients with the severity of grade A or B esophageal reflux, according to the Los Angeles classification, are enrolled.

Exclusion Criteria:

• Patients are excluded if they have taken antisecretory agents, including histamine-2 receptor antagonist and PPI, within two weeks prior to the panendoscopy. The following conditions are also excluded: the presence of peptic ulcers, pregnancy, major medical problems (including hypertension, liver cirrhosis, COPD, asthma, renal failure and congestive heart failure), or previous gastric surgery. Patients who have an allergy history to dexlansoprazole or lansoprazole are also excluded.