Nationwide Epidemiological Survey of Acute Pancreatitis in Japan

Objectives: A nationwide epidemiological survey of acute pancreatitis (AP) was performed to estimate the number of patients with AP in 2011 in Japan and to clarify the clinical features. Methods: The first survey was performed by sending a questionnaire to randomly selected 4175 departments to determine the number of hospitalized patients with AP during 2011. The second survey was conducted by sending a questionnaire to departments in which hospitalized patients with AP were treated based on the first questionnaire. Evaluation of the AP severity was based on the revised severity scoring system of AP of the Japanese Ministry of Health, Labor and Welfare (2008). Results: The estimated total number of patients with AP in 2011 was 63,080 (95% confidence interval, 57,678-68,484), with an overall prevalence rate of 49.4 per 100,000 population. The male-to-female ratio was 1.9. The mean age was 58.5 in male and 65.3 in female patients. Alcoholic AP was the most common in male and gallstone AP was the most common in female patients. The overall mortality of AP was 2.6%, and in severe AP, 10.1%. Conclusions: The number of patients with AP is still increasing. The revised severity scoring system provided a more precise prediction of prognosis.