A clinical trial to evaluate the efficacy and safety of PPI/sodium alginate therapy compared with PPI in nonerosive reflux disease

INTERVENTION: Drug : 3 arms (Control arm) PPI monotherapy group: [Omeprazole 20mg, 1 time/day, before meal (breakfast) + Placebo alginic acid 20mL/time, 3 4 times/day, between meals] x 4weeks (Test arm) PPI+Alginate combination therapy group: [Omeprazole 20mg, 1 time/day, before meal (breakfast) + Alginic acid(50mg/mL) 20mL/time, 3 4 times/day, between meals] x 4weeks (Exploratory arm) Alginate monotherapy group: ]Placebo omeprazole 20mg, 1 time/day, before meal (breakfast) + Alginic acid(50mg/mL) 20mL/time, 3 4 times/day, between meals] x 4weeks CONDITION: Diseases of the digestive system PRIMARY OUTCOME: resolution of NERD symptom in the last 7 consecutive days (%, patient diary) SECONDARY OUTCOME: Changes of NERD symptom score (patient diary) Investigator's assessment for NERD symptom NERD symptom free days during 4 treatment weeks (%, patient diary) overnight NERD symptom free days during 4 treatment weeks (%, patient diary) Patient Assessment of Upper GastroIntestinal Disorders‐Quality of Life(PAGI‐QOL) survey score change Patient Assessment of Upper Gastrointestinal Disorders‐Symptom Severity Index (PAGI‐SYM) survey score change Reflux‐Disease‐Questionnair(RDQ) survey score change INCLUSION CRITERIA: 1) age of 20 79 years old 2) NERD patient suffering heartburn or regrugitation(either one) in past 7 days over 2 days of moderate to severe level or over 4 days of mild symptoms 3) volentary agreement with signed informed consent