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In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Context: To summarise the present evidence for an association between circulating fibrinogen or D-dimer and presence of abdominal aortic aneurysm (AAA) presence.', 'MEDLINE database was searched to identify all case-control studies that compared plasma fibrinogen or D-dimer concentrations between patients with AAA and subjects without AAA. For each study, data regarding fibrinogen or D-dimer concentrations in both the AAA and control groups were used to generate mean differences (MDs) and 95% confidence intervals (CIs). Study-specific estimates were combined using inverse variance-weighted average of logarithmic MDs in both fixed- and random-effects models.', 'Our search identified 10 eligible studies including 834 cases with AAA and 6971 controls without AAA for fibrinogen and six studies including 264 patients with AAA and 403 subjects without AAA for D-dimer. Pooled analysis demonstrated significantly higher fibrinogen (fixed-effects MD, 0.37gl(-1); 95% CI: 0.30-0.44gl(-1)) and D-dimer (random-effects MD: 415.36ngml(-1); 95% CI: 128.97-701.76ngml(-1)) concentrations in the AAA group than those in the control group.\Question: Are plasma fibrinogen and D-dimer concentrations associated with the presence of abdominal aortic aneurysm : a systematic review and meta-analysis?
Output:
We found that plasma fibrinogen and D-dimer concentrations are likely to be higher in cases with AAA than control subjects. Higher plasma fibrinogen and D-dimer concentrations may be associated with the presence of AAA.