Background : Since little is known about the prevalence of patients with functional gastrointestinal disorders (FGID), this study was performed to clarify the prevalence of FGID, especially functional dyspepsia (FD), in new patients of an outpatient clinic with primary care physicians in Japan. Methods : We analyzed consecutive outpatients (n = 5183) who first visited the Department of General Medicine, Asahikawa Medical College Hospital, between April 2004 and March 2009. Results : Out of 5813 patients, 818 (14.1%) visited because of abdominal symptoms. Final diagnoses of the 818 patients were FGID (n = 320, 39.1%), organic gastrointestinal diseases (n = 237, 28.9%), organic non-GI disease (n = 135, 16.5%), and others (n = 126, 15.4%). The 320 patients with FGID had FD (n = 170), irritable bowel syndrome (IBS) (n = 68), and other FGIDs (n = 88). The rate of FGID or FD in all patients was 5.5% or 2.9%, respectively. Among outpatients (n = 381) who complained of upper abdominal symptoms, approximately 45% had FD. There was no gender difference in the frequency of FGID, FD, or IBS in all ages of patients. A lower incidence of FD was shown in female patients over 70 years old and a higher incidence of IBS in male patients under 29 years old. Discussion : These results suggest that the prevalence of FGID, especially FD, is very high in an outpatient clinic with primary care physicians in Japan.
