Advanced complicated diabetes mellitus is associated with a reduced risk of thoracic and abdominal aortic aneurysm rupture: a population-based cohort study

Studies have associated diabetes mellitus (DM) with the reduced risk of abdominal aortic aneurysm and thoracic aortic aneurysm and dissection. We used the national insurance data of Taiwan to examine these correlations for an Asian population. The association was also evaluated by DM severity.We identified 160,391 patients with type 2 DM diagnosed from 1998 to 2008 and 646,710 comparison subjects without DM, frequency matched by diagnosis date, sex and age (mainly the elderly). The DM severity was partitioned into advanced and uncomplicated status according to DM-related comorbidities.By the end of 2010, the overall pooled incidence rate of thoracic aortic aneurysm and abdominal aortic aneurysm was 15% lower in the type 2 DM cohort than in non-DM cohort, with an adjusted hazard ratio of 0.64 [95% confidence interval (CI) 0.56-0.74] in the multivariable Cox model. Patients with advanced type 2 DM were significantly associated with reduced thoracic aortic aneurysm rupture and abdominal aortic aneurysm without rupture, with adjusted hazard ratios of 0.50 (95% CI 0.35-0.71) and 0.53 (95% CI 0.40-0.69), respectively. Uncomplicated type 2 DM was also associated with reduced abdominal aortic aneurysm without rapture (aHR = 0.58, 95% CI 0.45-0.74).Our results demonstrate that patients with diabetes in this Asian population have reduced prevalence of thoracic and abdominal aortic aneurysms. The observed paradoxical inverse relationship between severity of DM and aortic aneurysms is clear. Further research is required to investigate the underlying mechanisms for the reduced risk of aortic aneurysms associated with diabetes.