Impact of diabetes on postoperative outcomes following colon cancer surgery

Background: Diabetes is the sixth most common cause of death in the US and causes significant postoperative mortality and morbidity. Objective: To characterize the impact of diabetes among patients undergoing surgery for colorectal cancer. Design: This is is a retrospective cohort study. Participants: Patients in the Nationwide Inpatient Sample (NIS) who had undergone colorectal cancer surgery between 1998 and 2005. Measurements: Using multivariate regression, we determined the association of diabetes status with postoperative mortality, postoperative complications, and length of stay. Key Results: An estimated 218,534 patients had undergone surgery for colorectal cancer. We categorized subjects by the presence of diabetes, the prevalence of which was 15%. Crude postoperative in-hospital mortality was lower among diabetics compared to non-diabetics (2.5% vs. 3.2%, P<0.0001). Adjusted mortality was 23% lower in those with diabetes compared to non-diabetics (aOR 0.77; 95% CI: 0.71-0.84). Diabetics also had lower adjusted post-operative complications compared to non-diabetics (aOR 0.82; 95% CI: 0.79-0.84). In uninsured individuals and patients <50 years of age, there was no protective association between diabetes and either in-hospital mortality or postoperative complications. Conclusions: In patients undergoing colorectal cancer surgery, those with diabetes had a 23% lower mortality and fewer postoperative complications compared to non-diabetics. The mechanisms underlying this unexpected observation warrant further investigation.