This study aims to determine the prevalence of symptomatic gastroesophageal reflux disease (GERD) in children aged 8-9 years and 12-13 years in the Czech Republic. Participants are recruited through schools and complete a web-based questionnaire assessing reflux-related symptoms. Children reporting pyrosis or regurgitation undergo a stepwise diagnostic evaluation that includes a standardized proton pump inhibitor (PPI) trial, upper endoscopy when indicated, and 24-hour pH-impedance monitoring for those with inconclusive findings. These procedures allow classification into confirmed GERD, reflux hypersensitivity, or functional pyrosis. All children undergoing diagnostic testing complete a validated quality-of-life questionnaire. The study will provide population-based prevalence estimates and evaluate symptom burden and potential risk factors associated with pediatric GERD.

This cross-sectional, population-based study is designed to estimate the prevalence of symptomatic gastroesophageal reflux disease (GERD) in children aged 8-9 years and 12-13 years in the Czech Republic. The study uses a multi-stage, guideline-based diagnostic algorithm to differentiate confirmed GERD from functional pyrosis and reflux hypersensitivity. Participants are recruited through primary schools and grammar schools selected to reflect national demographic characteristics. Parents and children receive study information and a link to a secure web-based survey. The initial questionnaire collects data on oesophageal symptoms (pyrosis and regurgitation), prior proton pump inhibitor (PPI) use, and selected demographic and environmental variables. Children reporting symptoms suggestive of GERD proceed through a structured diagnostic pathway. The first step is a standardized PPI trial, consisting of 14 days of symptom recording before and 14 days during PPI therapy at an age-appropriate dose. A clinically meaningful reduction in symptom intensity is considered diagnostic for GERD. Children without a positive response undergo upper endoscopy to evaluate for esophagitis (Los Angeles grade C/D), strictures, or Barrett's esophagus. If endoscopy is normal or inconclusive, 24-hour pH-impedance monitoring is performed to assess reflux burden and symptom association. Findings are classified into GERD, reflux hypersensitivity, or functional pyrosis according to established consensus criteria. All participants undergoing PPI testing, endoscopy, or pH-impedance monitoring complete a validated pediatric quality-of-life assessment to characterize the functional impact of symptoms across diagnostic categories. Epidemiologic and demographic variables collected in the initial survey will be used to evaluate potential risk factors for symptomatic GERD. The study follows standard clinical procedures routinely performed at the investigators' institution. All data are de-identified and stored in a secure REDCap database. Results will inform prevalence estimates of pediatric symptomatic GERD in Central Europe and support future clinical guidance and public health planning.

Administrative Information Sponsor: University Hospital in Motol Principal Investigator: Tereza Lerchova, M.D., Ph.D. Co-Investigators: Associate Professor Ondrej Hradsky, M.D., Ph.D.; Jana Duskova, MD; Professor Jiri Bronsky, M.D., Ph.D.

Study Sites: Nationwide (primary schools across the Czech Republic) Trial Registration: [To be assigned - ClinicalTrials.gov]

The project has been supported by the Czech Health Research Council (CHRC): project number NW25J-09-00146.

Inclusion Criteria:

• age group of 8 - 9 years and 12 - 13 years
• school attendance ability

Exclusion Criteria:

• psychomotor impairment

Participants will be recruited through a nationwide network of primary schools using voluntary participation after parental consent. The sample is designed to approximate a representative cross-section of Czech children aged 8-9 and 12-13 years but is based on non-probability sampling.