Long-term incidence of gallstone disease after bariatric surgery: results from the nonrandomized controlled Swedish Obese Subjects study

Background: Gallstone disease is a known short-term complication of bariatric surgery; little is known of the long-term incidence.

Objectives: The aim of this study was to investigate the association between bariatric surgery and long-term incidence of gallstone disease.

Settings: A total of 25 surgery departments and 480 primary healthcare centers in Sweden.

Methods: The Swedish Obese Subjects study is a prospective, controlled study comparing the effects of bariatric surgery with usual care with a follow-up of 20 years, including 4047 individuals. The current report includes all participants without previous or concomitant cholecystectomy (n = 3597). Operative techniques used in the surgery group (n = 1755) were gastric bypass (n = 236), vertical banded gastroplasty (n = 1202), and gastric banding (n = 317). The control group (n = 1842) received customary treatment for obesity. Gallstone disease was a predefined secondary endpoint in the Swedish Obese Subjects study and the primary endpoint of this report. Data were obtained by cross-checking our study database with the Swedish National Patient Register of diagnosis and procedures.

Results: In the surgery and control groups, respectively, there were 307 and 252 first-time events of symptomatic gallstone disease and 230 and 170 cholecystectomies (log-rank P < .001, both outcomes). Bariatric surgery was associated with an increased risk of symptomatic gallstone disease, with a more pronounced risk during the first years of follow-up (P = .002) and an increased risk for cholecystectomy but with no time-varying effect (P = .213).

Conclusions: Bariatric surgery increases the risk for symptomatic gallstone disease and cholecystectomy, especially during the first years following treatment.