On December 4, 2024, Vasco Knight@ASVS 2024 was held as scheduled at the Athenee, a Luxury Collection Hotel, Bangkok, Thailand. With the theme of "Innovation and Future", the conference brought together top experts in the field of vascular surgery from around the world, focusing on the latest treatment technologies of the aorta and abdominal aorta, the future development trend of China's medical technology, and related practical operations and innovative research and development.

The epidemiological profile of abdominal aortic aneurysm (AAA) varies by region. This study analyzed the gender and age distribution characteristics of hospitalized AAA patients in seven major geographical regions of China and compared them with international data. The results showed that the number of AAA patients in China was younger, and there were significant differences in sex ratio and age distribution among different climates, altitudes, and economic regions. These findings provide the basis for accurate diagnosis and individualized treatment, and underscore the importance of a national data platform.

Introduction 

The incidence of AAA varies significantly between countries and regions. In developed countries, the incidence of AAA in people over 65 years of age ranges from 1.1% to 6%, with males occurring as high as 4% to 7% and females occurring at 1% to 2%. In contrast, the incidence of AAA in China is about 0.9%, but large-scale, multicenter gender and age distribution analysis is lacking. This study aims to fill this epidemiological research gap and reveal the gender and age characteristics of AAA patients in China and their regional differences.

Materials and methods

Study design and data sources

● Data collection: Typical hospitals in 22 provinces, 5 autonomous regions and 4 municipalities directly under the central government covering seven geographical regions of China. 

● Study period: January 2013 to December 2023. 

● Number of cases: A total of 39,762 patients were enrolled, including 32,403 males and 7,359 females. 

● Standard: Primary diagnosis is AAA (ICD-10 codes: I71.1 to I71.6). Analyze metrics ● Gender ratio and age distribution. 

● Regional differences: Eastern, Central, Northern, Northwestern, Northeastern, Southern, Southwestern. 

● Influencing factors: altitude, climate type, economic level, etc. Statistical methods 

● ANOVA was used to analyze the age and gender differences between different regions. 

● Cox regression was used to analyze the relationship between relevant factors and patient characteristics.

Results & Analysis

01. Regional differences

● Age distribution: patients in the eastern region are the oldest, and patients in the northwest region are the youngest.

● Gender ratio: The proportion of male patients was the highest in the southern region (87.45%), and the lowest in the southwest region (76.17%). 

● Climate and altitude influences: the tropical monsoon climate region has the highest proportion of age and males; 

The age of patients is the lowest in the plateau climate zone, and the proportion of women is the highest. With the increase of altitude, the age of patients and the proportion of males decreased significantly (P<0.001).

02 Economic disparities 

● The age and male ratio of patients in high-income areas were significantly higher than those in middle-income areas (P<0.001). 

● Younger patients and a higher proportion of women are present in areas with lower economic levels.

03 Comparison with international data 

●Compared with the same latitude, Beijing and Tianjin had the lowest age and male ratio (P<0.001).

● 16.22% of patients under the age of 60 in China are much higher than those in other countries.

Discuss

Younger trends:The younger trend of AAA patients in China may be related to the earlier age of onset of chronic diseases (such as hypertension and hyperlipidemia), reflecting the younger trend of systemic vascular diseases. 

Potential causes of gender and age distribution 

● Gut-vascular axis: Dietary habits in different regions lead to differences in the composition of intestinal flora, affecting the level of metabolites (such as TMAO), and then regulating vascular function. 

● Hypoxic effect: The hypoxic environment at high altitude activates hypoxia-inducible factors and accelerates vascular aging. 

● Low temperature stimulation: Long-term low temperature environment may increase the risk of AAA in women. 

● Imbalance in medical resources: The level of medical care and disease knowledge in low- and middle-income areas is low, which may lead to delays in diagnosis. 

Case sharing 

Case 1: Male patient in northern China 

● Background: 65 years old, living in northern China, complaining of abdominal pain. 

● Diagnosis: AAA with peripheral inflammation. 

● Treatment: Open repair surgery was undertaken, and there was no recurrence after two years of postoperative follow-up. 

Case 2: Female patient in Southwest China 

● Background: 59 years old, living in southwest China, AAA was detected in physical examination. 

● Diagnosis: no obvious symptoms, AAA diameter of 4.5cm. 

● Treatment: Endovascular repair technique was selected, and it was stable for one year after surgery. 

Summary and outlook Summary of the study 

● There are obvious regional differences in AAA patients in China, and the trend of younger age is significant. 

● Gender and age distribution are influenced by multiple factors, including geographical, economic and environmental conditions. Future research directions 

● Establish a national or even global AAA patient data platform to further characterize patients. 

● In-depth study of the effects of intestinal flora, hypoxia and low temperature on the pathogenesis of AAA. 

● Optimize the hierarchical diagnosis and treatment model and improve the level of disease management in low-income areas.