Circadian and seasonal rhythms of acute upper gastrointestinal bleeding in Beijing

Abstract

OBJECTIVE: To investigate the circadian and seasonal patterns in the presentation of acute upper gastrointestinal bleeding (AUGIB) in Beijing, China. METHODS: Medical records of the Beijing Emergency Medical Service System (EMSS) for 1 August 2005 to 31 July 2007 were reviewed; all patients diagnosed with AUGIB were included in the study. RESULTS: 2580 patients were recorded in the EMSS system with a diagnosis of AUGIB during the study period. 1888 (73%) were male and 692 (27%) were female. Mean age was 53+/-20 years for male patients and 63+/-21 years for female patients. Significant differences in the presentation of AUGIB were noticed between seasons (p<0.001) and months (p<0.001). The number of cases in cold months (from December to April) was significantly higher than that in warm months (June to September). There was a significant circadian rhythm; there were fewer cases during daytime hours compared with night-time hours (p<0.001). CONCLUSIONS: The presentation of AUGIB in Beijing has a clear seasonal and circadian rhythm. Circadian and seasonal rhythms associated with AUGIB may aid in identifying modifiable risk factors in individuals and populations.