Gallstone size and risk of pancreatitis

Background: The treatment of patients with gallstones who have suffered a first episode of acute biliary pain is controversial. Recent guidelines suggest that such patients may choose to observe the ''pattern'' of their pain over time before deciding about therapy. Objective: To determine clinical factors that would identify patients at high risk for 2 important complications: acute biliary pancreatitis and acute cholecystitis. Methods: We collected sociodemographic and clinical data on patients undergoing cholecystectomy after acute biliary pancreatitis, acute cholecystitis, or uncomplicated biliary pain. The physical characteristics of gallstones recovered at surgery were also recorded. Patients with pancreatitis and patients with cholecystitis were compared with patients with uncomplicated pain. Results: In univariate analyses, patients with acute pancreatitis were significantly more likely to have at least 1 gallstone smaller than 5 mm in diameter, 20 or more gallstones, gallstones described as mulberry shaped, and a lower total gallstone weight than patients with uncomplicated pain. Pancreatitis was unrelated to patient age, sex, race or ethnicity, use of alcohol or tobacco, or clinical comorbidity. In a logistic regression model, acute pancreatitis was associated with a stone diameter of less than 5 mm (odds ratio, 4.51; P=.007) and with mulberry-shaped gallstones (odds ratio, 2.25; P=.04). No sociodemographic, clinical, or gallstone characteristics were consistently associated with acute cholecystitis. Conclusions: Patients with at least 1 gallstone smaller than 5 mm in diameter have a more than 4-fold increased risk of presenting with acute biliary pancreatitis. A policy of watchful waiting in such cases is unwarranted.