The population prevalence of undetected abdominal aortic aneurysm in New Zealand Māori

Abstract

Background: The prevalence of abdominal aortic aneurysm (AAA) in Polynesian populations such as the New Zealand Māori has not been characterized. We measured this in a large population-based sample.

Methods: A cross-sectional population-based prevalence study was conducted as part of an AAA screening pilot; 2467 Māori men aged 54 to 74 years and 1526 women aged 65 to 74 years registered with a primary care practice in Auckland (New Zealand) were invited to be screened by abdominal ultrasound between June 2016 and March 2018. Patients with pre-existing AAA disease and those with terminal conditions or circumstances that would make them unlikely to benefit from screening were excluded. The prevalence rate of AAA in Māori women was calculated with a cutoff definition of 27 mm as well as with the normal 30-mm definition (used in men). A log-binomial regression model estimated the prevalence rate at exactly 65 years for the purpose of comparison with screened populations in the United Kingdom.

Results: The crude prevalence rate of undiagnosed AAA in Māori men aged 60 to 74 years was 3.6%. In women, it was 1.7% at the 30-mm threshold and 2.3% at 27 mm. The prevalence rate at exactly 65 years of age was calculated from the log-binomial regression model to be 2.7% (confidence interval [CI], 2.0%-3.8%) in men, 0.9% (CI, 0.4%-2.2%) in women at the 30-mm threshold, and 1.5% (CI, 0.7%-3.0%) in women at the 27-mm threshold. Among smokers, the crude prevalence rates were 7.5% (CI, 4.9%-11.5%) in men and 6.9% (CI, 4.1%-11.5%) in women (30 mm+).

Conclusions: The prevalence of undiagnosed AAA in New Zealand Māori men is considerably higher than in screened populations of equivalent age in the United Kingdom and Sweden. Prevalence rates in New Zealand Māori women are close to those of screened British men. New Zealand should consider implementing a population-based screening program for Māori men and conduct further research into the health impact of screening Māori women.

Keywords: Abdominal aortic aneurysm; Ethnicity; Māori; New Zealand; Prevalence; Race; Screening.