Socio-Economic Determinants of Abdominal Aortic Aneurysm Rupture Incidence: A Nationwide Geospatial Study

The impact of socio-economic factors on abdominal aortic aneurysm (AAA) rupture are poorly understood at a geospatial level, but they are important considerations in the targeted distribution of preventive resources such as screening and treatment. This study aimed to map the nationwide geospatial distribution of AAA ruptures in Aotearoa New Zealand and to analyse associations with socio-economic factors.

A nationwide, retrospective, geospatial analysis of all AAA ruptures between January 2000 and December 2019 in Aotearoa New Zealand was performed using national registry mortality and hospitalisation data within a Bayesian framework. Standardised incidence ratios (SIRs) of AAA rupture were calculated for populations grouped by socio-economic factors (deprivation, ethnicity, and urban accessibility). Geospatial analysis was performed using Bayesian Poisson regression modelling to provide smoothed estimates of AAA rupture incidence at the small community level. The association between rupture incidence and small area level smoking rates, Māori population proportion, urban accessibility, and socio-economic deprivation (SED) was examined through geospatially linked data.

Over the 20 year study period, 5 942 fatal and non-fatal AAA ruptures were identified. High AAA rupture incidence was geospatially clustered into persistent hotspots. SED (coefficient 3.39, 95% credible interval [CrI] 2.38 - 4.49) and smoking prevalence (coefficient 1.14, 95% CrI -0.03 - 2.27) were associated with increased AAA rupture incidence and this was persistent over the study, despite the AAA rupture incidence falling from 1.05/1 000 person years (95% CrI 0.60 - 1.85) in 2000 - 2006, to 0.65/1 000 person years (95% Crl 0.38 - 1.13) in 2013 - 2019. SIRs were elevated in socio-economically deprived, Māori, and rural communities.

AAA rupture is clustered into geographically defined and persistent high risk communities in Aotearoa New Zealand. High deprivation communities bear an excess burden of AAA rupture, as do the indigenous Māori population, consistent with entrenched health inequities following colonisation. This should inform the management and implementation of AAA screening and treatment.