Association of peripheral artery disease with abdominal aortic aneurysm growth

Objective: To determine whether an association of peripheral artery disease (PAD) with abdominal aortic aneurysm (AAA) growth is positive, none, or negative, a meta-analysis of all available studies was performed through a systematic literature search. Methods: MEDLINE and Embase databases were searched until July 2015 by the use of PubMed and Ovid Web-based search engines. The search terms were enlargement, expansion, growth, or progression; and abdominal aortic aneurysm. Studies that fulfilled the following criteria were included: (1) AAA patients with PAD and those without PAD as the population and (2) data of AAA growth as the outcomes. By means of growth rates in patients with and without PAD for each study, we generated standardized mean differences (SMDs) and their 95% confidence intervals (CIs). Results: Of 612 initially screened publications that were potentially relevant, 11 eligible studies that reported the correlation between PAD and AAA growth were identified, and a total of 4573 patients with AAA were included. A pooled analysis of the 11 studies demonstrated a statistically significant association of PAD with lower growth rates of AAA (SMD, 0.18; 95% CI, 0.25 to 0.11; P < .00001). In addition, separately combining seven adjusted effect estimates did not substantively alter the pooled estimate (SMD, -0.17; 95% CI, -0.25 to -0.09; P < .0001). No significant publication bias was observed. Conclusions: PAD is likely negatively associated with AAA growth. Further research is required to explain why PAD negatively correlates with AAA growth despite a positive correlation with AAA presence.