# The relationship between abdominal aortic aneurysm diameter and its risk factors: a retrospective cohort study

## TL;DR

Younger age and current smoking are linked to larger abdominal aortic aneurysms, while other risk factors like hypertension show no significant correlation.

## Contribution

This study identifies current smoking and younger age as significant factors associated with increased aneurysm diameter, while other common risk factors are not.

## Key findings

- Smokers had significantly larger aneurysms than non-smokers and former smokers.
- Patients aged ≤65 years had larger aneurysms than those aged 66–75 years.
- Multivariate analysis showed a weak relationship between risk factors and aneurysm size (R² = 0.0608).

## Abstract

Abdominal aortic aneurysm is defined as a focal and persistent dilatation of the abdominal portion of the aorta to a diameter ≥50% larger than the diameter of adjacent segments and involving all three layers of the vessel wall.

To evaluate whether risk factors (diabetes mellitus, hypertension, dyslipidemia, smoking, and age) influence aneurysm expansion.

This is a retrospective observational study of a series of cases that included 299 patients treated from January 2007 to January 2020, separated into exposed and unexposed groups by risk factors. Student’s t test was used to assess whether mean aneurysm diameters showed statistically relevant differences between groups. A multivariate regression analysis was also conducted with the same groups.

Smokers had larger aneurysms than those who had never smoked (p=0.002) and than former smokers (p<0.01) and patients ≤65 years old had larger diameters compared to patients aged 66 to 75 years old (p=0.0226). There were no significant correlations with the other risk factors (diabetes mellitus, dyslipidemia, hypertension). Multivariate regression analysis confirmed the same result, but with a coefficient of determination of 0.0608. Furthermore, smokers, patients with hypertension, patients with dyslipidemia, and patients without diabetes had higher frequencies of much larger aneurysm diameters.

It was observed that age ≤65 years and current smoking were related to greater aneurysm diameter. In contrast, the same statistical relationship was not observed for hypertension, absence of diabetes, or dyslipidemia, since there was a greater frequency of discrepant values for these groups. Studies are needed with a more comprehensive analysis of determinants of aneurysm diameter.

O aneurisma de aorta abdominal é definido como uma dilatação focal e persistente da porção abdominal da aorta ≥ 50% do diâmetro dos segmentos adjacentes, envolvendo as três camadas do vaso.

Avaliar como os fatores de risco (diabetes melito, hipertensão arterial, dislipidemia, tabagismo e idade) influenciam na expansão do diâmetro aneurismático.

Trata-se de um estudo observacional retrospectivo de uma série de casos que incluiu 299 pacientes atendidos entre janeiro de 2007 e janeiro de 2020, divididos entre os grupos de expostos e não expostos aos fatores de risco. Utilizou-se o teste t de Student para avaliar a relação com o diâmetro aneurismático. Ademais, foi realizada uma análise de regressão multivariada com esses grupos.

Fumantes demonstraram aneurismas maiores em comparação aos que nunca fumaram (p = 0,002) e aos ex-fumantes (p < 0,01), assim como pacientes com idade ≤ 65 anos em comparação aos pacientes entre 66 e 75 anos (p = 0,0226). Não houve correlação significativa com os demais fatores de risco (diabetes melito, dislipidemia e hipertensão). A análise de regressão multivariada confirmou o mesmo resultado, porém com um coeficiente de determinação de 0,0608. Além disso, pacientes tabagistas, hipertensos, dislipidêmicos e não diabéticos apresentaram maiores frequências de diâmetros muito elevados.

Observou-se que idade ≤ 65 anos e tabagismo atual estão relacionados com maiores diâmetros aneurismáticos. Apesar da mesma relação estatística não ter sido provada acerca de hipertensão, ausência de diabetes melito e dislipidemia, houve uma maior frequência de valores discrepantes para esses grupos. São necessários estudos com uma compreensão mais abrangente dos determinantes do diâmetro aneurismático.