Variation in care in individuals hospitalised with abdominal aortic aneurysm in nine high-income countries: a cross-sectional cohort study

Abstract Background Abdominal aortic aneurysms (AAA) can be safely repaired using either endovascular aneurysm repair (EVAR) or open repair when intact, but after rupture morbidity and mortality are extremely high. Treatment patterns and outcomes for intact AAA are likely to differ between countries due to differences in AAA screening policies, health system capacity and payment approaches, and other factors, such as demographics and lifestyle, but are poorly studied. Methods We conducted a retrospective serial cross-sectional cohort study of adults aged ≥66 years hospitalised for with an intact AAA and repair procedure in the same admission between 2011 and 2019 in nine countries (US, Canada, England, Denmark, Netherlands, Switzerland, Taiwan, South Korea and Israel) using population-representative administrative data. We investigated age-sex standardised (to the 2019 US population) repair rates (open repair or EVAR) and health system performance measures, including hospital length of stay (LOS), 30-day readmission, and all-cause mortality (30 days and 1 year). Results The number of intact AAA hospital admissions between 2011 and 2019 ranged from 1,290 in Israel to 199,764 in the US. The rates of intact AAA repair per 1000 population varied between countries and over time, from 0.11 per 1000 (South Korea) to 0.69 per 1000 (US) in 2011 and from 0.14 per 1000 (Taiwan) to 0.57 per 1000 (the Netherlands) in 2019. Most countries saw a decline in the rate of AAA repair over the study period. The proportion repaired using open repair vs EVAR also varied widely across the countries. In the US, Israel and Taiwan open repair was used in 11% or fewer cases whereas in the remaining countries we observed open repair in 25.1 % (South Korea) to 56.7% (Denmark) of cases. (Figure 1) Mortality was generally higher following open repairs compared to EVAR in all countries. In 2019, following EVAR, 30-day mortality varied from 0.6% (8.1% at 1 year) in South Korea to 2.3% (11.7% at 1 year) in Israel and following open repair varied from 2.9 (4.4% at 1 year) in England to 7.6% (15.1% at 1 year) in the US. (Figure 2) Mean hospital LOS in 2019 ranged from 2.5 days (US) to 12.2 days (South Korea), following EVAR and from 9.1 days (Taiwan) to 21.5 days (South Korea) following open repair. The 30-day readmission rate in 2019 ranged from 8.1% (US) to 31.8% in Israel following EVAR and from 11.4% (US) to 22.2% (South Korea) following open repair. Conclusions We observed substantial between-country variation in surgical approaches, mortality, and health system performance measures for AAA. Further research is needed to understand and plan optimal, evidence-based AAA screening and treatment strategies.Rates of EVAR and open repairAdjusted 30-day all-cause mortality