AIM:To investigate variations in the incidence of peptic ulcers(PUs) in Taiwan by day of the week within age subgroups.METHODS:Ambulatory care data were retrieved from the Longitudinal Health Insurance Database 2000.There were 7204 subjects≥18 years-old with an emergency room admission claim for the treatment of PUs,resulting in a total of 9234 emergency room visits for PUs between 2009 and 2011.Data was divided into the seven days of the week and an additional variable for holidays.One-way analysis of variance was used to examine associations among the daily mean number of PU emergency room admissions and holidays/weekends/weekdays.RESULTS:One-way analysis of variance showed that there was a significant difference in emergency room admissions for PUs by the day of the week(P<0.001),with admission more likely to occur on Sundays or holidays than weekdays within the total and working populations.The weekday patterns of admission were similar for the patients aged 18-64 years and≥65years of age.Holidays,followed by Sundays,had higher PU admissions than the mean daily PU emergency room admissions.Furthermore,inclusion of only those treated for PUs with hemorrhage or perforation,Sundays and holidays had higher mean emergency room admissions than other days.Inclusion of patients who diagnosed with Helicobacter pylori infection,only holidays had higher mean emergency room admissions than other days.Inclusion of patients who had been prescribed non-steroidal anti-inflammatory drugs(NSAIDs)for over30 d,Sundays and holidays had higher mean PU ER admissions than other non-holiday weekdays.CONCLUSION:There is a higher incidence of emergency room admission for PUs on weekends than on weekdays for the total and working populations. AIM: To investigate variations in the incidence of peptic ulcers (PUs) in Taiwan by day of the week within age subgroups. METHODS: Ambulatory care data were retrieved from the Longitudinal Health Insurance Database 2000.There were 7204 subjects ≥18 years-old with an emergency room admission claim for the treatment of PUs, resulting in a total of 9234 emergency room visits for PUs between 2009 and 2011. Data was divided into the seven days of the week and an additional variable for holidays. One-way analysis of variance was used to examine associations among the daily mean number of PU emergency room admissions and holidays / weekends / weekdays.RESULTS: One-way analysis of variance showed that there was a significant difference in emergency room admissions for PUs by the day of the week ( P <0.001), with admission more likely to occur on Sundays or holidays than weekdays within the total and working populations. The weekday patterns of admission were similar for the patients aged 18-64 years and ≥65y ears of age.Holidays, followed by Sundays, had higher PU admissions than the mean daily PU emergency room admissions.Furthermore, inclusion of only those treated for PUs with hemorrhage or perforation, Sundays and holidays had higher mean room admissions than other days. Inclusion of patients who diagnosed with Helicobacter pylori infection, only holidays had higher mean emergency room admissions than other days. Occlusion of patients who had been prescribed non-steroidal anti-inflammatory drugs (NSAIDs) for over 30 d, Sundays and holidays had higher mean PU ER admissions than other non-holiday weekdays. CONCLUSION: There is a higher incidence of emergency room admission for PUs on weekends than on weekdays for the total and working populations.