The effect of diabetes mellitus on perioperative outcomes after colorectal resection: a national cohort study

Background Diabetes mellitus is a significant modulator of postoperative outcomes and is an important risk factor in the patient selection process. We aimed to investigate the effect of diabetes mellitus and use of insulin on outcomes after colorectal resection using a national cohort. Methods Adults with a recorded colorectal resection in England between 2010 and 2020 were identified from Hospital Episode Statistics data linked to the Clinical Practice Research Database. The primary outcome was 90-day mortality. Secondary outcomes included hospital length of stay (LOS) and readmission within 90 days. Results Of the 106 139 (52 875, 49.8% male) patients included, diabetes mellitus was prevalent in 10 931 (10.3%), 2145 (19.6%) of whom had a record of use of insulin. Unadjusted 90-day mortality risk was 5.7%, with an increased adjusted hazard ratio (aHR) for people with diabetes mellitus (aHR 1.28, 95% confidence interval [CI] 1.19–1.37, P<0.001). This risk was higher in both people with diabetes using insulin (aHR 1.51, 95% CI 1.31–1.74, P<0.001) and not using insulin (aHR 1.22, 95% CI 1.13–1.33, P<0.001), compared with those without diabetes. Ninety-day readmission occurred in 20 542 (19.4%) patients and this was more likely in those with diabetes mellitus (aHR 1.23, 95% CI 1.18–1.29, P<0.001). Median (inter-quartile range) LOS was 8 (5–15) days and was higher in people with diabetes mellitus (adjusted time ratio 1.10, 95% CI 1.08–1.11, P<0.001). Conclusions People with diabetes mellitus undergoing colorectal resection are at a higher risk of 90-day mortality, prolonged LOS, and 90-day readmission, with use of insulin associated with additional risk.