Risk of adhesive bowel obstruction after abdominal surgery. A national cohort study of 665,423 Danish women.

BACKGROUND: Adhesive bowel obstruction is associated with considerable morbidity and mortality, but the magnitude of the risk is debated. METHOD: In a national cohort of all Danish women with an abdominal operation (N = 665,423) between 1977 and 2013, the risk of adhesive bowel obstruction was assessed by Cox multiple regression. Covariates were the number of abdominal operations, the surgical methods, the anatomical site involved, and the calendar year. RESULTS: In the cohort, 1.4% experienced an episode of adhesive bowel obstruction. The risk increased 33-43% during the study period, was lower after gynecological and obstetrical procedures compared to gastrointestinal (HR 0.36 [0.34-0.38]), lower after laparoscopic compared to laparotomic surgery (HR 0.51 [0.48-0.54]) and increased proportionally after each additional operation. CONCLUSIONS: The risk of adhesive bowel obstruction after abdominal operations depends on the site of earlier operations, the method of access and the number of earlier operations.