We performed a retrospective review of the NIS database from 1998 to 2007. Patients undergoing major gastrointestinal surgery were identified by ICD-9 procedure codes: esophageal (42.4), gastric (43.5-43.9), small intestine (45.6), large intestine (45.7–45.8 and 17.3), rectal (48.4–48.6), hepatic (50.2–50.3), biliary (51.3 and 51.6), and pancreatic (52.5–52.7). Exclusion criteria included age over 60 y and under 18 y, multiple operations, and a sexual developmental disorder (25.52, 75.27, and 25.9). The primary outcome measure was in-hospital death.
A total of 307,124 patients were identified, of whom 50.3 % were women. Overall, there were 6574 (2.14 % ) deaths; 2.45 % of men and 1.84 % of women died (P < 0.001). In multivariate analysis, women were 21.1 % less likely to die than men (OR = 0.789, 95 % CI = 0.74–0.84). When subset analysis was performed, women had improved mortality in the following types of surgery: gastric (OR = 0.751, 95 % CI = 0.60–0.94), small intestine (OR = 0.704, 95 % CI = 0.63–0.79), large intestine (OR = 0.845, 95 % CI = 0.77–-0.93), hepatic (OR = 0.562, 95 % CI = 0.41–0.77), and pancreatic (OR = 0.658, 95 % CI = 0.49–0.89, see Fig. 1).
Our study demonstrates that women may have improved outcomes after some types of major gastrointestinal surgery; however, the mechanism by which this occurs is unclear. Future studies are needed to further evaluate this interesting phenomenon.