Diabetes Is Not Associated with the Risk of Rupture Among Patients with Abdominal Aortic Aneurysms - Results From a Large Danish Register Based Matched Case Control Study From 1996 to 2016.

Objective: Numerous studies have shown a paradoxical protective effect of diabetes on the development and progression of abdominal aortic aneurysm (AAA). The aim of this study was to investigate whether the protective role of diabetes on AAA extends to rupture, given the presence of an AAA.

Methods: This was a register based case control study. Patients with ruptured AAA (RAAA) were matched 1:1 with patients undergoing elective surgery for AAA by sex, age, and year of diagnosis. Multiple conditional logistic regression was performed to estimate the odds ratio (OR) associating a diagnosis of diabetes with RAAA. No protocol was registered.

Results: From 1996 to 2016, there were 6293 potential people with RAAA. A total of 898 people with a RAAA were excluded since no matching controls existed. This left 5 395 cases in the study. The cases had a median age of 75, and 85.4% were men. Diabetes was defined by hospital diagnosis or the redemption of antidiabetic prescriptions within one year. Comparing cases with controls and the presence of diabetes, a significant crude OR of 0.82 (95% confidence interval [CI] 0.71-0.95) was found. When adjusting for confounders OR increased to 0.97 (CI 0.83-1.14). Stratifying by age and year of diagnosis did not change the results markedly. OR associating RAAA with diabetes was significantly elevated in women (adjusted OR 1.82 [CI 1.17-2.81]). Of the 5395 cases, the overall 30 days mortality was 58% (n = 3145). Using Cox regression, a crude hazard ratio (HR) of 1.06 (CI 0.93-1.22) was found for the 30 day mortality and having diabetes compared with not having diabetes. Adjusting for index year, male sex, and age had little effect on this estimate (HR 1.11 [CI 0.97-1.28]).

Conclusion: Diabetes was not found to protect against RAAA, given the presence of an AAA. Furthermore, diabetes did not increase the risk of dying within 30 days of RAAA.