Natural History of Incidentally Discovered Gallstones

Asymptomatic gallstones often are discovered during abdominal imaging for other reasons. In most studies of the natural history of gallstones, patients were aware of having gallstones, which could bias interpretation and management of subsequent abdominal symptoms. In this study from Denmark, researchers identified 664 people (age range, 30–70; median age, 60) in whom gallstones were identified on ultrasound (done during a larger prospective health study). Participants were not informed of ultrasound results; health histories documented that only 10% were previously aware of having gallstones.

During median follow-up of 17 years, 20% of participants developed gallstone-related events: 8% had “complicated events” (i.e., acute cholecystitis or common duct stones) and 12% had “uncomplicated events” (i.e., cholecystectomy for a noncomplicated indication, or clinical diagnosis of cholelithiasis without treatment). Significant predictors of any gallstone-related event were having a large stone (>10 mm; hazard ratio, 2.3), having multiple stones (HR, 1.7), and female sex (HR, 2.3). For example, 10-year risk for a gallstone event was 3% in men with one small stone and 23% in women with multiple stones (and at least one >10 mm). Large stone size was particularly predictive of acute cholecystitis or cholecystectomy for a noncomplicated indication, whereas having multiple stones was particularly predictive of a complicated common duct stone presentation.