Rupture of abdominal aortic aneurysms (rAAA) is associated with high mortality. Use of angiotensin converting enzyme inhibitors (ACE‐inhibitors) and angiotensin receptor blockers (ARBs) has been suggested to reduce the risk of rAAA. This nationwide, combined case–control and follow‐up study aims to examine the possible impact of preadmission renin–angiotensin system blockade on the risk of rAAA and case fatality following rAAA.

Using Danish healthcare registries, a combined case–control and follow‐up study was conducted among all patients with a first‐time hospital admission for rAAA and AAA controls without rupture in Denmark from 1996 to 2012. Individual‐level data were obtained on preadmission drug use, comorbidity, socioeconomic factors, healthcare services use, and death.

The adjusted age‐matched and sex‐matched odds ratios (adj. OR) were 0.96 (95% confidence interval (CI): 0.85; 1.07) for rAAA for current ACE‐inhibitor users and 0.93 (95%CI: 0.79; 1.09) for current ARB users compared with never users. Propensity score‐matched analyses yielded similar results for current ACE‐inhibitor users (adj. OR: 1.02, 95%CI: 0.88; 1.19) and current ARB users (adj. OR: 1.02, 95%CI: 0.83; 1.26). The total 30‐day mortality rate after hospital admission was 61.0% in current ACE‐inhibitor users compared with 59.4% in non‐ACE‐inhibitor users (adjusted mortality rate ratio (adj. MRR) 1.06, 95%CI: 0.94; 1.20) and 58.6% in current ARB users compared with 59.9% in non‐ARB users (adj. MRR: 0.96, 95%CI: 0.82; 1.14).

Use of renin–angiotensin system blockade was not associated with a lower risk of rAAA or lower case fatality following rAAA. Copyright © 2015 John Wiley & Sons, Ltd.