Effect of smoking cessation on abdominal aortic aneurysm growth: a systematic review and network meta-analysis

INTRODUCTION: To compare the effect of smoking cessation in abdominal aortic aneurysm growth compared to active smokers and non-smokers.EVIDENCE ACQUISITION: A systematic review and Network Meta-Analysis was performed following the PRISMA guidelines using a registered protocol (CRD42021295315). We searched MEDLINE, CENTRAL, PsycInfo, Web of Science Core Collection and OpenGrey databases from inception to January 2022 for comparative studies reporting on abdominal aortic aneurysm growth according to smoking habits. AAA was defined as an infra-renal aortic diameter >3 cm. The main outcome was to estimate the mean difference of abdominal aortic aneurysms growth between smokers, former smokers, and nonsmokers. The estimates were pooled through a random-effects model network meta-analysis and heterogeneity assessed through the I2 statistic.EVIDENCE SYNTHESIS: After 567 abstracts reviewed and 17 full text studies, six studies were included in the review and meta-analysis. Studies reported data from 1987-2017, encompassing a population of 2960 people with diagnosis of AAA, which 972 were active smokers, 1254 were former smokers and 679 were nonsmokers. Based on the network estimates, we did not find a statistically significant difference between AAA growth rate differences between former smokers and non-smokers (MD 0.05, 95% CI: -0.36 to 0.47). However, we found statistically significant differences between former smokers and active smokers (MD -0.45, 95% CI: -0.83 to -0.06) and active smokers versus non-smokers (MD 0.50, 95% CI: 0.16 to 0.85).CONCLUSIONS: Smoking cessation seems to reduce the growth rate of AAA to rates similar to non-smokers, being a potential therapeutic target. These findings should lead to a higher awareness of the importance of smoking eviction in AAA patients and to future studies on this matter.