Meta-analysis of the growth rates of abdominal aortic aneurysm in the Chinese population

Background Several studies on the growth rates of abdominal aortic aneurysm (AAA) in Chinese population have been conducted; however, this issue remains unclear. The aim of this study is to systematically review published data of the AAA growth rates among people in China. Methods We conducted a comprehensive search of multiple databases to identify all studies of AAA growth in the Chinese population from inception until June 2017. AAA growth rates were combined to yield the growth rates at specified aneurysm diameter ranges, with using a random-effects model or fixed-effects model according to heterogeneity. Results A total of 8257 studies were initially identified and only 4 studies were eventually included. A random-effects analysis showed that the growth rates of AAA in Chinses population is ranging from 0.18 cm/year to 0.75 cm/year. The pooled mean growth rates among individuals with aneurysm measuring 3.0-3.9 cm, 4.0-5.9 cm and >= 6.0 cm in diameter were 0.21 cm/year (95% CI: 0.19 cm/year to 0.23 cm/year), 0.38 cm/year (95% CI: 0.33 cm/year to 0.43 cm/year), and 0.71 cm/year (95% CI: 0.64 cm/year to 0.77 cm/year) respectively. Further analysis found that the pooled mean growth rates for individuals with small AAA (diameters measuring 3.0-4.9 cm) was 0.28 cm/year (95% CI: - 0.06 cm/year to 0.61 cm/year)`and for individuals with large AAA (diameters >= 5.0 cm) was 0.75 cm/year (95% CI: 0.20 cm/year to 1.3 cm/year). Finally, meta-regression showed a strong trend of linear relationship between AAA growth rate and aneurysm diameter. Conclusions The growth rates of AAA in the Chinese population increase with AAA enlargement and appear to range from 0.18 cm/year in the smallest AAAs to 0.75 cm/year when the diameter exceeds 6 cm. However, based on current studies, it is difficult to estimate the accurate average AAA growth rate in Chinese patients. More large-scale, high-quality studies are required to achieve that. Overall, AAA growth rate increase with increased aneurysm diameter.