Ethnic inequalities in incidence, survival and mortality from abdominal aortic aneurysm in New Zealand

Smoking data quality of primary care practices in comparison with smoking data from the New Zealand Māori and Pacific abdominal aortic aneurysm screening programme: an observational study

BACKGROUND

Quality smoking data is crucial for assessing smoking-related health risk and eligibility for interventions related to that risk. Smoking information collected in primary care practices (PCPs) is a major data source; however, little is known about the PCP smoking data quality. This project compared PCP smoking data to that collected in the Māori and Pacific Abdominal Aortic Aneurysm (AAA) screening programme.

METHODS

A two stage review was conducted. In Stage 1, data quality was assessed by comparing the PCP smoking data recorded close to AAA screening episodes with the data collected from participants at the AAA screening session. Inter-rater reliability was analysed using Cohen's kappa scores. In Stage 2, an audit of longitudinal smoking status was conducted, of a subset of participants potentially misclassified in Stage 1. Data were compared in three groups: current smoker (smoke at least monthly), ex-smoker (stopped > 1 month ago) and never smoker (smoked < 100 cigarettes in lifetime).

RESULTS

Of the 1841 people who underwent AAA screening, 1716 (93%) had PCP smoking information. Stage 1 PCP smoking data showed 82% concordance with the AAA data (adjusted kappa 0.76). Fewer current or ex-smokers were recorded in PCP data. In the Stage 2 analysis of discordant and missing data (N = 313), 212 were enrolled in the 29 participating PCPs, and of these 13% were deceased and 41% had changed PCP. Of the 93 participants still enrolled in the participating PCPs, smoking status had been updated for 43%. Data on quantity, duration, or quit date of smoking were largely missing in PCP records. The AAA data of ex-smokers who were classified as never smokers in the Stage 2 PCP data (N = 27) showed a median smoking cessation duration of 32 years (range 0-50 years), with 85% (N = 23) having quit more than 15 years ago.

CONCLUSIONS

PCP smoking data quality compared with the AAA data is consistent with international findings. PCP data captured fewer current and ex-smokers, suggesting ongoing improvement is important. Intervention programmes based on smoking status should consider complementary mechanisms to ensure eligible individuals are not missed from programme invitation.

The Global and Regional Prevalence of Abdominal Aortic Aneurysms: A Systematic Review and Modeling Analysis

OBJECTIVE

To estimate the global and regional prevalence and cases of abdominal aortic aneurysms (AAAs) in 2019 and to evaluate major associated factors.

BACKGROUND

Understanding the global prevalence of AAA is essential for optimizing health services and reducing mortality from reputed AAA.

METHODS

PubMed, MEDLINE, and Embase were searched for articles published until October 11, 2021. Population-based studies that reported AAA prevalence in the general population, defined AAA as an aortic diameter of 30 mm or greater with ultrasonography or computed tomography. A multilevel mixed-effects meta-regression approach was used to establish the relation between age and AAA prevalence for high-demographic sociodemographic index and low-and middle-sociodemographic index countries. Odds ratios of AAA associated factors were pooled using a random-effects method.

RESULTS

We retained 54 articles across 19 countries. The global prevalence of AAA among persons aged 30 to 79 years was 0.92% (95% CI, 0.65-1.30), translating to a total of 35.12 million (95% CI, 24.94-49.80) AAA cases in 2019. Smoking, male sex, family history of AAA, advanced age, hypertension, hypercholesterolemia, obesity, cardiovascular disease, cerebrovascular disease, claudication, peripheral artery disease, pulmonary disease, and renal disease were associated with AAA. In 2019, the Western Pacific region had the highest AAA prevalence at 1.31% (95% CI, 0.94-1.85), whereas the African region had the lowest prevalence at 0.33% (95% CI, 0.23-0.48).

CONCLUSIONS

A substantial proportion of people are affected by AAA. There is a need to optimize epidemiological studies to promptly respond to at-risk and identified cases to improve outcomes.

Use of radiological information system data in Clinical Portal database to screen for missed abdominal aortic aneurysms

INTRODUCTION

New Zealand lacks a formal abdominal aortic aneurysm screening programme and owing to its rural nature, many patients have limited access to vascular surgery. Patients with vascular emergencies often have limited treatment options locally, especially if they present perimortem. In our small hospital in Whanganui, with the nearest vascular centre more than 150km away, there are cases of aneurysms diagnosed incidentally on radiology reporting but lost to follow-up.

METHODS

Clinical Portal (CP) is a widely used patient-centred dashboard for viewing health information that is managed by Orion Health. A search strategy utilising the CP common database was devised that aimed to find aneurysms which were not followed up. This search was performed retrospectively for all imaging within a 5-month period.

RESULTS

Some 294 scans were flagged and 53 patients with aneurysms were found. Of these patients, 36 had follow-up by the ordering provider and 17 (32%) were found to have been lost to follow-up.

CONCLUSIONS

Our pilot study demonstrated high rates of loss to follow-up and a lack of communication of important health information across multiple health disciplines in the region, and represents a potential method for identifying 'lost' aneurysms. For patients in rural communities, this may be critical to preventing future complications from aneurysmal disease.

Incidence and Outcomes of Abdominal Aortic Aneurysm Repair in New Zealand from 2001 to 2021

Purpose: The burden of abdominal aortic aneurysms (AAA) has changed in the last 20 years but is still considered to be a major cause of cardiovascular mortality. The introduction of endovascular aortic repair (EVAR) and improved peri-operative care has resulted in a steady improvement in both outcomes and long-term survival. The objective of this study was to identify the burden of AAA disease by analysing AAA-related hospitalisations and deaths. Methodology: All AAA-related hospitalisations in NZ from January 2001 to December 2021 were identified from the National Minimum Dataset, and mortality data were obtained from the NZ Mortality Collection dataset from January 2001 to December 2018. Data was analysed for patient characteristics including deprivation index, repair methods and 30-day outcomes. Results: From 2001 to 2021, 14,436 patients with an intact AAA were identified with a mean age of 75.1 years (SD 9.7 years), and 4100 (28%) were females. From 2001 to 2018, there were 5000 ruptured AAA with a mean age of 77.8 (SD 9.4), and 1676 (33%) were females. The rate of hospitalisations related to AAA has decreased from 43.7 per 100,000 in 2001 to 15.4 per 100,000 in 2018. There was a higher proportion of rupture AAA in patients living in more deprived areas. The use of EVAR for intact AAA repair has increased from 18.1% in 2001 to 64.3% in 2021. The proportion of octogenarians undergoing intact AAA repair has increased from 16.2% in 2001 to 28.4% in 2021. The 30-day mortality for intact AAA repair has declined from 5.8% in 2001 to 1.7% in 2021; however, it has remained unchanged for ruptured AAA repair at 31.6% across the same period. Conclusions: This study highlights that the incidence of AAA has declined in the last two decades. The mortality has improved for patients who had a planned repair. Understanding the contemporary burden of AAA is paramount to improve access to health, reduce variation in outcomes and promote surgical quality improvement.

Pathogenic mechanisms and the potential of drug therapies for aortic aneurysm

Aortic aneurysm is a permanent focal dilation of the aorta. It is usually an asymptomatic disease but can lead to sudden death due to aortic rupture. Aortic aneurysm-related mortalities are estimated at ∼200,000 deaths per year worldwide. Because no pharmacological treatment has been found to be effective so far, surgical repair remains the only treatment for aortic aneurysm. Aortic aneurysm results from changes in the aortic wall structure due to loss of smooth muscle cells and degradation of the extracellular matrix and can form in different regions of the aorta. Research over the past decade has identified novel contributors to aneurysm formation and progression. The present review provides an overview of cellular and noncellular factors as well as enzymes that process extracellular matrix and regulate cellular functions (e.g., matrix metalloproteinases, granzymes, and cathepsins) in the context of aneurysm pathogenesis. An update of clinical trials focusing on therapeutic strategies to slow abdominal aortic aneurysm growth and efforts underway to develop effective pharmacological treatments is also provided.

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

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.

Health gains, costs and cost-effectiveness of a population-based screening programme for abdominal aortic aneurysms

BACKGROUND

Abdominal aortic aneurysm (AAA) rupture carries a high fatality rate. AAAs can be detected before rupture by abdominal ultrasound imaging, allowing elective repair. Population-based screening for AAA in older men reduces AAA-related mortality by about 40 per cent. The UK began an AAA screening programme offering one-off scans to men aged 65 years in 2009. Sweden has a similar programme. Currently, there is no AAA screening programme in New Zealand. This cost-utility analysis aimed to assess the cost-effectiveness of a UK-style screening programme in the New Zealand setting.

METHODS

The analysis compared a formal AAA screening programme (one-off abdominal ultrasound imaging for about 20 000 men aged 65 years in 2011) with no systematic screening. A Markov macrosimulation model was adapted to estimate the health gains (in quality-adjusted life-years, QALYs), health system costs and cost-effectiveness in New Zealand. A health system perspective and lifetime horizon was adopted.

RESULTS

With New Zealand-specific inputs, the adapted model produced an estimate of about NZ $15 300 (€7746) per QALY gained, with a 95 per cent uncertainty interval (UI) of NZ $8700 to 31 000 (€4405 to 15 694) per QALY gained. Health gains were estimated at 117 (95 per cent UI 53 to 212) QALYs. Health system costs were NZ $1·68 million (€850 535), with a 95 per cent UI of NZ $820 200 to 3·24 million (€415 243 to €1·65 million).

CONCLUSION

Using New Zealand's gross domestic product per capita (about NZ $45 000 or €22 100) as a cost-effectiveness threshold, a UK-style AAA screening programme would be cost-effective in New Zealand.

Correcting for Body Surface Area Identifies the True Prevalence of Abdominal Aortic Aneurysm in Screened Women

OBJECTIVE

Recently, the prevalence of abdominal aortic aneurysm (AAA) using screening strategies based on elevated cardiovascular disease (CVD) risk was reported. AAA was defined as a diameter ≥30 mm, with prevalence of 6.1% and 1.8% in men and women respectively, consistent with the widely reported AAA predominant prevalence in males. Given the obvious differences in body size between sexes this study aimed to re-evaluate the expanded CVD risk based AAA screening dataset to determine the effect of body size on sex specific AAA prevalence.

METHODS

Absolute (26 and 30 mm) and relative (aortic size index [ASI] equals the maximum infrarenal aorta diameter (cm) divided by body surface area (m²), ASI ≥ 1.5) thresholds were used to assess targeted AAA screening groups (n = 4115) and compared with a self reported healthy elderly control group (n = 800).

RESULTS

Male AAA prevalence was the same using either the 30 mm or ASI ≥1.5 aneurysm definitions (5.7%). In females, AAA prevalence was significantly different between the 30 mm (2.4%) and ASI ≥ 1.5 (4.5%) or the 26 mm (4.4%) thresholds.

CONCLUSION

The results suggest the purported male predominance in AAA prevalence is primarily an artefact of body size differences. When aortic size is adjusted for body surface area there is only a modest sex difference in AAA prevalence. This observation has potential implications in the context of the ongoing discussion regarding AAA screening in women.

Evaluation of the relationship between plasma lipids and abdominal aortic aneurysm: A Mendelian randomization study

Studies have reported that higher circulating levels of total cholesterol (TC), low-density lipoprotein (LDL) cholesterol and lower of high-density lipoprotein (HDL) cholesterol may be associated with increased risk of abdominal aortic aneurysm (AAA). Whether dyslipidemia causes AAA is still unclear and is potentially testable using a Mendelian randomization (MR) approach. We investigated the associations between blood lipids and AAA using two-sample MR analysis with SNP-lipids association estimates from a published genome-wide association study of blood lipids (n = 188,577) and SNP-AAA association estimates from European Americans (EAs) of the Atherosclerosis Risk in Communities (ARIC) study (n = 8,793). We used inverse variance weighted (IVW) MR as the primary method and MR-Egger regression and weighted median MR estimation as sensitivity analyses. Over a median of 22.7 years of follow-up, 338 of 8,793 ARIC participants experienced incident clinical AAA. Using the IVW method, we observed positive associations of plasma LDL cholesterol and TC with the risk of AAA (odds ratio (OR) = 1.55, P = 0.02 for LDL cholesterol and OR = 1.61, P = 0.01 for TC per 1 standard deviation of lipid increment). Using the MR-Egger regression and weighted median methods, we were able to validate the association of AAA risk with TC, although the associations were less consistent for LDL cholesterol due to wider confidence intervals. Triglycerides and HDL cholesterol were not associated with AAA in any of the MR methods. Assuming instrumental variable assumptions are satisfied, our finding suggests that higher plasma TC and LDL cholesterol are causally associated with the increased risk of AAA in EAs.

Comparison of three targeted approaches to screening for abdominal aortic aneurysm based on cardiovascular risk

BACKGROUND

Abdominal aortic aneurysm (AAA) continues to be a significant health burden yet few countries have implemented a comprehensive screening programme. Screening typically places emphasis on men aged over 65 years; however, there is concern that other at-risk groups may be underidentified. The present study examined three potential screening strategies based on cardiovascular risk.

METHODS

The prevalence of AAA was determined by abdominal ultrasound imaging in over 50-year-olds of either sex undergoing coronary angiography, vascular laboratory assessment of peripheral arterial disease, or community-based cardiovascular disease (CVD) event risk assessment. A fourth group, consisting of volunteers aged over 60 years who had no symptoms or signs of cardiovascular disease, was used as a comparator group.

RESULTS

A total AAA prevalence of 4·4 per cent was detected across all three strategies (137 of 3142 individuals), compared with 1·0 per cent in the CVD-free group. Male sex, age and smoking were all associated with greater AAA prevalence. Although AAA prevalence was lowest using the community-based strategy, those with an AAA detected were on average 7 years younger than those with AAAs detected with the other two strategies (P < 0·001).

CONCLUSION

Different strategies, based on CVD risk, resulted in AAA prevalence rates that were significantly greater than that in CVD-free individuals. This may provide opportunities for a targeted approach to community AAA screening in parts of the world where more sophisticated national screening programmes do not exist.

Identification of microRNAs associated with abdominal aortic aneurysms and peripheral arterial disease

BACKGROUND

MicroRNAs are crucial in the regulation of cardiovascular disease and represent potential therapeutic targets to decrease abdominal aortic aneurysm (AAA) expansion. The aim of this study was to identify circulating microRNAs associated with AAA.

METHODS

Some 754 microRNAs in whole-blood samples from 15 men with an AAA and ten control subjects were quantified using quantitative reverse transcriptase-PCR. MicroRNAs demonstrating a significant association with AAA were validated in peripheral blood and plasma samples of men in the following groups (40 in each): healthy controls, controls with peripheral arterial disease (PAD), men with a small AAA (30-54 mm), those with a large AAA (over 54 mm), and those following AAA repair. MicroRNA expression was also assessed in aortic tissue.

RESULTS

Twenty-nine differentially expressed microRNAs were identified in the discovery study. Validation study revealed that let-7e (fold change (FC) -1·80; P = 0·001), miR-15a (FC -2·24; P < 0·001) and miR-196b (FC -2·26; P < 0·001) were downregulated in peripheral blood from patients with an AAA, and miR-411 was upregulated (FC 5·90; P = 0·001). miR-196b was also downregulated in plasma from the same individuals (FC -3·75; P = 0·029). The same miRNAs were similarly expressed differentially in patients with PAD compared with healthy controls. Validated and predicted microRNA targets identified through miRWalk revealed that these miRNAs were all regulators of AAA-related genes (vascular cell adhesion molecule 1, intercellular cell adhesion molecule 1, DAB2 interacting protein, α1-antitrypsin, C-reactive protein, interleukin 6, osteoprotegerin, methylenetetrahydrofolate reductase, tumour necrosis factor α).

CONCLUSION

In this study, circulating levels of let-7e, miR-15a, miR-196b and miR-411 were differentially expressed in men with an AAA compared with healthy controls, but also differentially expressed in men with PAD. Modulation of these miRNAs and their target genes may represent a new therapeutic pathway to affect the progression of AAA and atherosclerosis.

Real geographies and virtual landscapes: exploring the influence on place and space on mortality Lexis surfaces using shaded contour maps

This paper describes how shaded contour plots, applied to mortality data from the Human Mortality Database, can be used to compare between nations, and start to tease out some of the ways that place and space matters. A number of shaded contour plots are presented, in order to describe the age, period and cohort effects which are apparent within them. They show variations between different subpopulations within the same nation, over time, and between nations. In illustrating these intra- and international variations in the patterns, we hope to encourage the development of hypotheses about the influence of such factors on mortality rates. We conclude with a brief discussion about how such hypotheses might be developed into statistical models, allowing for more rigourous testing of hypotheses and projection across time, place and space.