Nationwide epidemiological survey of acute pancreatitis in Japan

Objectives: A nationwide epidemiological survey was conducted to estimate the number of patients treated for acute pancreatitis (AP) in 2007 in Japan and to clarify the clinicoepidemiological features of AP. Methods: In the first survey, a simple questionnaire was used to inquire about the number of patients with AP who visited the hospital in the year 2007. This questionnaire was directly mailed to the heads of 3027 facilities. The second questionnaire was forwarded to those facilities from which patients with AP were reported on the first questionnaire. Results: The estimated total number of patients treated for AP in 2007 was 57,560 (95% confidence interval, 48,571-66,549), with an overall prevalence rate of 45.1 per 100,000 population. The sex ratio (male-female) of the patients was 2.0, with a mean age of 56.6 years in men and 64.6 years in women. Alcoholic AP was most common in men and gallstone AP in women. The overall mortality rate of AP was 1.9% and, in severe cases, 8.0%. Conclusion: The number of patients with AP increased about 3-fold during this decade (19,500 in 1998 to 57,560 in 2007), and the mortality rate of AP was reduced from 7.4% in 1998 and 2.9% in 2003 to 1.9% in 2007.